As Apple's iPad sales continue to surge (3 million last time I looked) and with manufacturers lining up to announce the competition, it looks like tablet computing is here to stay. Whilst it's easy to see why ipads appeal to the sofa surfers amongst us (27% of owners never take it out of the house ), it's harder to see where it fits into businesses where most mobile workers will have a laptop anyway.

One niche (and I stress, it is a niche) where the ipad works very nicely for me is as a personal document library. It's so handy to take to meetings, or to go and sit somewhere comfortable to go through a long document (maybe with a nice Latte). Yes, you can do this with a laptop, but no it's not as pleasant.

As we've seen with the word processors (check out my review of Pages), whilst consumption of documents is managed very well, creation and editing of documents is limiting. One can easily draft a report or letter on the go - but most businesses will have custom headed templates for most documentation, or have mail merge and macros built into templates designed in Microsoft Office. Put short, right now, you're still going to need your laptop, which makes £400+ on the ipad hard to justify on top of that.

That said, the ipad isn't a fixed platform. It's developing and growing through the App store and whilst we wait for someone to come up with a word processor to rival Microsoft's offering (actually, just one that allows 'Check Changes' would do for now) a developer called 'Aji, LLC' has gone and developed a fine application that allows you to annotate PDF documents.

The company where I work gets through over 3 million printed pieces of paper every year. A lot of these print outs are documents which the user has printed for themselves to scribble over, cross stuff out, make notes and so on for someone else to read back and act upon. Sometimes these are even scanned back into electronic documents so that they can be emailed, but I expect more often than not, they go into the internal post, where they will take a day or two to get to the next person's desk. Sounds pretty inefficient, doesn't it?

This is a problem I think iAnnotate can help with and at £5.99 it could quickly pay itself back in reduced print costs alone. The reason I think people tend to print out is because paper is easier to read closely than the computer screen, but also interacting with text on a computer in this way does not feel intuitive to a lot of people. The iPad with its finger driven touch screen and well designed interface could overcome all of this.

When you first run iAnnotate, you're presented with a 'Getting Started' PDF, which will introduce you to all the major functions in the app. It's a testament to the simplicity of the design of this program that the instructions only run to 3 pages and each of these contains simple explanations of each feature alongside a large screen graphic of the buttons you'll need to tap. Flicking up and down through the PDF also shows how responsive this program is at managing PDF files - as certainly some PDF readers get quite bogged down and jerky when you're trying to jump around between pages and so on. You can have several PDFs open in tabs and still the app is quick and responsive.

So you've got a PDF to scribble all over, what sort of scribbling can you do? In the same way as Apple's Pages focused upon the most common word processor features that you would need, so to does iAnnotate. You can add text notes encased in speech bubbles, use the pencil mode to draw freehand, the ruler function allows straight lines to be drawn at any angle anywhere on the document and the highlighter allows you to highlight lines of text in easy swipes across the screen. Finally, if you need to underline or strikethrough text, again it's as easy and selecting the right option from the menu at the right of the screen and swiping your finger across the target text.

The whole thing feels very natural and, to me, as comfortable as a printed copy with a pen - certainly much easier to review later, or make changes to my edits should I need to. Those who wish to use a stylus (I'm not a fan, the ipad's screen technology is not ideal for them, but the best one I've tried is from Pogo), will be pleased to note that the latest version of the software is designed to respond to stylus use making it feel even more like a pen and paper experience.

Finally, as with any of these document viewers and editors that are fighting for space on your ipad, one of the big problems can be managing the documents that you wish to work with. The standard iTunes method (supported here) where you synchronise the files as part of a normal itunes sync is cumbersome and slow. Fortunately, Aji has included a good selection of methods to get your documents in and out.

My favourite is the newly included Dropbox support. Check out my earlier review for this essential addition to your ipad. Most applications like iAnnotate will open a dropbox file, but iAnnotate goes a step further by allowing you to save your changes back to your dropbox! You can also browse to PDFs available on the web, email them to yourself or download the free 'Aji PDF Service' software which allows you to synchronise lots of documents direct between your computer and your ipad with relative ease.

All in all, iAnnotate is an excellent piece of software and well priced for what it does. Also, it shows that even though it's early days, the ipad really is a contender as a productivtiy tool, as well as being a very nice toy.

For more information, check out this video tour uploaded by the Developer:

[youtube=http://www.youtube.com/watch?v=k3g_wYr-vDI]

Featured image used under 'Creative Commons' license, thanks to Targuman.