Google "rtcomm maemo" for more info.

It is the IM/VOIP app built into OS2008 (comes with the n810 and is a free upgrade for the n800) ... there is nothing new to install unless you want to play with newer test versions.

It *was* available for OS2007 as a beta version but now that they have put out a new beta version for OS2008, they don't seem to provide a link to the old version.

In any case, if you haven't already, OS2008 is worth the upgrade and it will be there automagically when you are done. Just remember the backup your settings first.