If you live in a major, metro area, open the yellow pages, and go to "coin dealers" or "numismatics". Then call them and see if they carry them (or can have them delivered to their shop for you to pick up). Other points:
1. Most dealers only accept cash (no checks, credit cards, etc.). So when visiting your dealer, you should allot time to first visit your bank and get the dough necessary to make your purchase.
2. Do NOT buy fractional ounces -- the dealers charge bigger markups for them.
3. Ask the dealer about sales tax. Some states charge tax, others don't. In CA, if I recall, your purchases are taxed (sales tax) for amounts less than $1,000. Over that amount, no sales tax applies.
4. When calling your dealers, ask them what their price is for (pick your favorite coin). Then compare that to the current gold quote -- that is their markup. Prices change all the time, but it gives you an idea what % markup they charge.
5. When it comes time for you to SELL some of your gold, I believe the dealer only reports transactions >$10k per day to the IRS. So you might want to keep that in mind....
I believe there are also web-based dealers. Though I cannot speak from any experience about them.
Good luck.