For better or for worse, the Apple AppStore has a bucketload of To-Do apps. If you're looking for a heavy-hitting [and location-aware] application designed specifically for the GTD mavens, you'll want OmniFocus ($19.99), and if you're looking for something a little lighter on the wallet, then Erica Sadun's free To-Do app might just be the answer.

But over the last few months, I've used and grown to love Cultured Code's application Things ($9.99). At the AppStore's debut, the number one qualm that I had with most To-Do apps was that my task lists were only ever accessible via the iDevice. However, just like OmniFocus, Things also works with the identically-named Mac sibling* and seamlessly syncs your to-dos over a local WiFi network.

The appeal of Things isn't just that it syncs, however. The application has always been easy to use, and unlike some competitors, friendly to those not versed in the David Allen Getting Things Done methodology. It's also got a delightful user interface: elegant, admittedly rather beautiful on the eye, the app is one of the few I've tried that actually kept using from day one.

In amongst a swathe of lacklustre applications on the AppStore,Things (like my other favourites Exposure and Twitterrific) is one of the few apps to look, feel and work as though Apple themselves produced it.

* The Mac-only desktop version of Things at the time of writing is still in 'preview' [beta], however the developers have announced it will launch at Macworld Expo in January for $49.

In my ongoing search for the ultimate software system for use with the Getting Things Done methodology, I've recently come across a real winner. Tracks is a web application that was built from the ground up for the purposes of implementing a GTD system. Written in Ruby on Rails, Tracks offers the familiar Projects and Contexts organization system made popular by David Allen's Getting Things Done system, coupled with the sparse graphical design and easy functionality made popular by well-known Ruby on Rails applications like Backpack, Basecamp and Ta-Da List. Now I should mention that Tracks is not affiliated in any way with 37 Signals (the maker of the other three web applications I mentioned), but it's clear that the Tracks developers are inspired by what 37 Signals have done. Plus, I'm sure it doesn't hurt that Rails was released by 37 Signals as a framework with which to get productive with Ruby very quickly.

The installation of Tracks is unfortunately not for the faint of heart; if you're someone that would shy away from installing a web server on your local machine, or don't have access to a Ruby-enabled web hosting account, installing Tracks probably isn't for you. If you are, there are a number of sets of instructions available.

For the rest of us, our best bet is to find a hosted solution. Since Tracks is by its very nature multi-user, it appears to have been a relatively straightforward task to build a hosted solution, and allow users to pay a monthly fee for access.

My favorite of these hosted offerings is called GTDTracks. GTDTracks is extremely affordable, at $1.49/month, and they offer regular backups and upgrades. I'd much rather about getting my stuff done than messing with upgrading a web application that I know very little about, so this option appeals to me a great deal. Plus, they take care of what is arguably my biggest fear with online hosted services, which is the question of how to get your data out if you decide to move on to something else. GTDTracks has a policy of allowing users to cancel their account at any time with no penalty (so you're not on the hook for more than a buck and a half at any given time), and you can take your data with you, exported as a plain text file that can be imported into another installation of Tracks, or simply mined for the data it contains.

Using Tracks is very straightforward - simply create Contexts and Projects as needed, then create Next Actions (essentially tasks) and associate them with the project and context they relate to. Due dates can be set through a convenient calendar widget. One nicely done element of the application is the Done page - one way to get inspired to get things done is to see what you've already accomplished. The Done page shows items that were completed in the last 24 hours, last 7 days and last 28 days, as well as a link for everything older than that.