A friend of mine is starting up a Shadowrun campaign, and I've never played in it before. Anything I should know going into it? I come from the experiences of mostly D&D 1-3.5, Star Wars d6, Dark Conspiracy 1-2, and... that's about it. A little bit of TROS.
It's 4th ed, if that matters.
Any tips, tricks, recommendations, overviews, or suggestions welcome.
[EDIT:] Is there any kind of rules overview or quickstart guide on the web somewhere for a free download?