It's possible that I'll need psychiatric hospitalization. What do I need to know?

I'm 23 years old, been dealing with a variety of mental health issues since my early teen years. I'll explain more, if necessary.

Anyway, things aren't very good right now, and it's possible that I'll need psychiatric hospitalization within the next few weeks or so. It's not something I'm necessarily opposed to, I just want to know what I should expect. I've never been hospitalized before (with the exception of stitches for a non-psych accident I had as a kid).

What long-term effects would hospitalization have on me? I assume that I won't ever be allowed to own a gun, but it would be a bad idea to have one anyway. I also figure that my health insurance would go up, but I have never counted on living long enough/being successful enough to get health insurance of my own, so it's a moot point. I guess I'm being rather pessimistic. Will hospitalization come up in background checks and keep me from getting a job with the state or the city? Would it prevent me from adopting a pet from the humane society someday?

If I do go in, would I be allowed to have my own clothing or an mp3 player? What about being there would actually help me get better... what happens there that I couldn't do at home? Would I be doing anything, or would I just be put in sort of a secure area with a few distractions until the crisis was over and then told to go back home?

If you've been in, do you have any advice?

Thanks.