Keeping organised can be tough sometimes and there are lots of different applications and tools designed to help you get organised.
It is written in C#/Mono, so you will need all the relevant Mono gubbins already installed to get it up and running. Here on Fedora 8, there isn't a package yet, so I'll run you through how to install it from source.
First of all, head to the Tasque download page and download the archive in whichever format you want. Once you've got it, extract it somewhere, then open a terminal in that directory.
It's a fairly standard compilation process:
$ make install # as root
Once that's done, it should show up under Office in your GNOME Applications menu. As soon as you load it up, you'll be given the option to integrate directly with Remember The Milk.
Clicking the Authorise button whisks you away to the RTM site, where you enter your username and password on the site itself and then allow API access for Tasque. Once you've done that, and clicked the button back in the app, your todo list syncs directly from the service.
By default, all your future tasks show up in the main window all together, but you can use the selection box at the top left to filter between what would appear as your different tabs in RTM.
In a similar vein, adding a task just by clicking the big button adds it directly to your RTM inbox, but again you can select which category to add it to using the arrow.
Once you've set up a task, you can then add more information such as a due date and notes. I found the due date interface to not work very well or very intuitively, requiring me to hold down the mouse on the - column to select a date from a pop-up list.
Tasque still is in its early days, and there are no official 'stable releases' yet, so this behaviour might be improved in future.
The syncing between RTM and Tasque as a desktop client works well. Any changes you make are synchronised almost instantly. My only concern on the reliance on the service is that Tasque appears to have no offline mode or cache of your tasks - i.e. at launch time you must have a connection to RTM or the application ceases to be of use.
Nevertheless, from what I've seen, Tasque is a simple approach to making Remember The Milk integrate well with the GNOME desktop, and despite some teething troubles is a must for any GNOME and RTM user.