How can I find someone to help me find my biological grandparents for free? Anonymously preferably, because my Dad has no idea he is adopted! Is that at all possible. I am supposed to be married in Sept of 09 and I would love to know if my Dad had any living relatives!

Anonymously and for free?

Not likely.

Spending money, you could hire a private investigator.

For free, you can TRY to register on online search sites, but most of the time searches must be started by the adoptee or by the birthparents.

I am in the same situation but the only difference is that my father knows the truth and refuses to talk or say anything about it. It can get a bit discouraging at times because we feel as though we need and want to know so bad... in the occasion that I get any leads on my situation I surely will let you know.
STAY ENCOURAGED!!