Great questions that need to be answered.
Your best bet would be to use an aromatase inhibitor (AI). These block the conversion (aromatization) of testosterone to estrogen, resulting in a lower circulating concentration of estrogen in the body. Arimidex (anastrozole) is probably the best choice. It's potency isn't too harsh and is the choice for most users.
Letrozole (femara) is too harsh and will pretty much zero your estrogen levels unless you're taking a fair amount of AAS, and too little estrogen is very unhealthy. Another popular choice is Aromasin (exemestane). It is much like arimidex in that is isn't too harsh. it is somewhat newer and many people are finding it to be a better choice. I would suggest either Arimidex or Aromasin.
The other category of applicable drugs would be selective estrogen receptor mediators (SERM), or as most call them, anti-estrogens. These work as already described in a previous post. They bind to selective estrogen receptors to block their action, but the high levels of estrogen are still circulating in the body.
This is likely not your best option as the high levels of estrogen will still interact with the non-mediated estrogen receptors. You may still have mood swings, hot flashes, feel like watching chick-flicks, etc. Some people don't get these reactions, others do.
If you're going long-term your best bet would be to get a prescription (for ensured availability and documentation) for an AI and check your estradiol and cholesterol levels after taking it until you find the optimal dose. If you're going short-term use (as in on an AAS cycle) I would suggest picking up a bottle from Chemone.com or another research company as it will likely be cheaper, depending on insurance.