Wired just setup a how-to wiki describing how to check yourself for genetic abnormalities. The wiki is pretty wimpy on details at the moment, but hopefully people will update it with more information soon. The wiki suggests the following 3 options for analyzing your DNA:

1. Visit a genetic counselor. These companies specialize in detecting specific genes

2. Scan your whole genome by using a testing company such as 23andMe or deCODEme. By scanning your entire genome you can check much more than your genes. You can check for a million or more genetic markers called SNPs.

3. Perform the test yourself at home! This requires a good deal of work on your part, but the tools required to analyze your genome at home do indeed exist and they will surely become more available, cheaper, and easy to use in the near future