Dependencies : GTK+, the TiLP framework [tilibs.tar.gz]

iPAQ port (old) : here

There's a script for *nix platforms (tested so far on multiple families of Linux distros), to make it easier for people to test bugfixes directly from SVN: it checkouts (or updates, if a previous checkout is present) libti* and tiemu from SVN, compiles and installs them. You can download the script here.
Be sure to look inside it: you can find information on the packages you need for a successful compilation, and modify the path for the checkout and the $PREFIX where the binaries are installed.

Important note: due to a bug in the firmware of the Titanium/USB, its support (Linux) may run into troubles. Read §1 of user's manual for more information.