I'm confused... I do all of this (including "video calling" with skype) on Maemo. All of the above things are "working" just fine.

@Joseph: I'd hardly call your answer "objective". Reality is that the OP has not at all clarified what he means by 3G. It could mean it wants the N900 to work on 3G on his preferred carrier which uses an unsupported frequency set (like AT&T in the US). In which case, he's SOL, since software can't change that. And again, in reality, "video calling" is not standard (or rather there are many competing standards), and it's not in common use in most markets. The US and Europe being examples of where less than 1% of calls use video (and that's including skype).

And before you say "who would ever be so dumb as to think software could change 3G frequencies", I'll remind you that many locked mult-band phones lock out 3G for competitors. I'll also point you to "apps working", which as noted above is kind of a dumb thing to say without qualifying what apps they're asking for. (The OP may want "WhatApp" or other commercial apps that have not supported the N900.)