I want to buy a melodica. But I'm a complete beginner with all keyboard instruments (I'm a below-average guitar player), so I have a few basic questions that I can't see answered anywhere on any forum, so either there are lots of people scratching their heads like me, or there will be lots of people scratching their heads at my ignorance once they read this post.

So, here are my questions:
1) Do I want a soprano or an alto? My intention is to play along to my music at home, maybe jam with some guitar players, woo some girls, nothing major.
2) What's the difference between a melodica in 'C' and in 'F' (for example). All the notes are there, right? Is it just that the lowest/highest notes are C on one and F on the other? Why is this good/bad?
3) Web literature on the melodica seems to be sparse. What should I be searching for? I'm guessing that if I want to be playing chords, "piano chords" and "left-hand piano techniques" are good and for melodies, "piano melodies" and "right-hand piano techniques".
4) Any other tips?
Thanks to everyone for humouring my ignorance.
Famico