Anyone using an SPF record?

I’m getting pretty badly flooded with bounces by some spammer idiot(s) who are forging addresses at my domain. I wanted to make it possible for those who are using SPF records to check and see that the mail with my address forged into it isn’t “permitted” to come from the spammer’s servers. Unfortunately, Dreamhost doesn’t provide any explicit support for this (though they will insert custom TXT records on request), and the documents I’ve read about it online are cryptic to say the least.

Has anyone implemented an SPF record for their domain(s) at Dreamhost? If so, can you tell me how to go about it? Thanks!