For all of you with a tight foreskin that won't go below the head, you really need to go to a doctor about it.
I have the same issue and when I was at the sexual health clinic (for other reasons) I mentioned it to the doctor and he checked it out, and he said it was good I pointed it out to him.
You really need to be able to pull it back all the way for a whole bunch of reasons, mainly to keep it all clean. All sorts of stuff can get stuck in there - urine, semen, sweat, etc. - and it'll start to smell, and might get infected.
When you're in the shower, and not erect, start by pulling it back as far as you can go without it hurting too much. It'll hurt a bit, but as long as the skin doesn't tear or rip it's ok. Once you get to the hurting point back it off and try again. Keep going that and after a while it will stretch.
Another reason you have to loosen it up is that if you have sex without a condom and you thrust too hard your foreskin can easily rip and that will hurt like anything, and bleed. It could also suddenly get pulled back further down your penis and get stuck there if it can't get over the helmet ridge (I'm not sure of the anatomical name for it). And that'll hurt too, really, really bad, and I know from experience
My doctor gave me a small tube of cream (Betamethasone) to put around the foreskin twice per day and it helped loosen it up a bit. It's still hard to pull it back all the way when I'm erect but it gets easier after a while, and it feels great when the head of your penis is exposed after being covered all your life. It's super sensitive, if you touch it with dry fingers it'll really hurt, but when it's in a vagina it feels better.
Sorry for the extra long post, but I've got this experience with the tight foreskin and I thought I'd share it with others, especially since up until a few months ago I thought I was the only one...
EDIT: I thought I'd add these sites for anyone who is interested:
http://www.circumstitions.com/Care.html
http://www.cirp.org/news/betamethasone2/
http://www.cirp.org/library/treatmen...sis/milanovic/
http://members.lycos.co.uk/origins/l...methasone.html