The first thing a new player whould do is join a faction, they'll get someone to pick you up and teach you how to move aroun in the game.
take a look at the factions here: http://www.swcombine.com/community/factions.php
How do you mean? Do you mean talk to, or have them in your party?
To talk to them, simply approach them on foot (not in a vehicle) and hail them from the scan screen (I think it is). To have them in your party, you need to buy them (or have them assigned to you by your faction).
"May the Grace of Ara go with you, and His Vengeance be wrought upon your enemies."
That sounds like an inactive PC you're talking to.
Look around the city you're in (Position > Scanners) for a NPC called 'Vehicle Rental' (or something along those lines) and head over to him/her. You'll be able rent a vehicle from them that'll allow you to move around much faster.
in darkness messages? no, not yet anyway. I wrote a messaging system for another project that was very similar to DM's but a whole lot faster and neater, 've been considering replacing DM's with it. If I do that 'll try and remember to enable signatures on it, unless there are a lot of complaints.