n interesting link I wanted to share(in regards to this): http://www.bleb.org/software/maemo/ At the bottom you will find some information about Citrix, which besides being a bit contradicting (it isn't, but it is easy possible?) might help some more advanced users a bit more. Meanwhile I'll be RDesktop-ing and/or OpenVNC-ing it through my PC.
Unfortunately, with the advent of 2006 OS and the use of EABI, older ARM Linux binaries will no longer work on the 770 without recompilation. Therefore, unless Citrix recompile and provide new binaries, or an open source client is made available, Citrix is not easily possible on a modern Maemo device.