@teamer
IF it's just XMPP, you don't need to program anything: maemo already has XMPP.
All you'd need is the username, and the password.

@didik.wahyono
I didn't find a link to the jar file at the whatsapp website. Can you send me the link?


In any case, I'm a developer, and I can give you a hand if you like - though I've never done anything for telepathy.

As a side note: why do you want whatsapp? There's plenty of IM protocols which are pretty open, free, and already supported. Why would you want a closed one, closed-source, and even pay-for one?