Good news for the people fortunate to still have an N900 but unfortunate to have a dependency on Facebook. I have adapted purple-facebook to work with the ancient library versions we have on Fremantle. The package is currently in extras-devel. Obviously you also need Pidgin.

This is just a port, so before reporting any bugs here, try to make sure that it is not an upstream problem. Currently I am aware of one Maemo-specific bug/inconvenience, which is the limited support for displaying emoji due to them being some exotic UTF glyphs not present in the default Maemo font.