how to make a new translation?

[Duarte Henriques]

Hi, I'm interested in making a portuguese (portugal) translation, and I 
have some questions:

- is the translation scheme the usual .po / .mo files ?
- can I just translate some modules (i.e. xffm seems a bit large to 
translate it all though I'd be happy to translate it, just not at the 
moment :)

So, if the answers are yes and yes, how can I get a .po file without 
getting all the source code?

thanks.

regards,
Duarte Henriques