A few tips:

-Make up a name and have the order mailed to a friend's house who isn't growing.
-Try ordering from companies who ship from countries that are not well known as seed suppliers. They're out there, you just have to look around. IOW, order from companies who do NOT ship from Canada, The Netherlands and The UK.
-Sending cash is a reasonable option. I've paid for several seed orders with cash only among several different companies and I've never had a problem.
-If you want to be *really* careful, remove the metaillic strip from the currency you are sending. The government can run the envelope through a scanner which will detect the strip and indicate money is inside and how many of each bill in enclosed. This may lead to problems with the company depositing/converting the cash, since it has been altered- some banks/countries are sticklers about the condition of the currency they receive.
-If your package is intercpeted by the feds, they will remove the seeds and send a letter in the package instead, stating the seeds have been confiscated. If this happens, don't freak out! Just find another place to get your seeds sent under a *new* fake name. the feds won't bother going to the recipient's house to bust them for a few stupid seeds.

Good luck and have fun!