Portrait HELP! (please)

[compleks]

I've gotten myself into a sticky situation, so I come crawling to the pros for help

So here's my situation.

My sister volunteered my services as a photographer to one of her friends.
Her friend is an apprentice hairdresser and has an assignment or competition which involves her doing hair, makeup etc... and photographing the end result.

Trouble is, I've never done any portrait photography and don't have the gear for it either. Her friend is apparently lending me a good camera (not sure what yet). Or I know I can borrow a Nikon D80 if I need to.

As far as I've hear she wants these photos taken in an alley.

Soooo, I need your help.
I need any advice I can get on portrait photography. It's not a life or death issue, but it would be nice to get some half decent photos if possible.

Thanks all

[i speak in math]

I think there is probably plenty of blog posts on the main page about this topic. Search portraits or something and see how many come up.