How do I get a receipt for iTunes purchases?

Receipts should be automatically mailed to you. There's nothing you need to do (or can do) other than confirm that your current email address is correct in your iTunes Store account and make sure no anti-spam filter is blocking emails from Apple. It sometimes can take a couple of days for a receipt to be sent.

You can always look up purchases by logging into your iTunes Store account and going to the Purchase History.

EDIT: Is there any way to speed up how quickly I getthr receipt though?

No, sorry, there isn't.
Regards.

Message was edited by: Dave Sawyer

I haven't gotten an itunes store receipt since Dec 2009.
You can always look in your purchase history through itunes.