Here is a recomendation from a sports medicine doctor who does a Q and A over on Rxmuscle:
"Next would be gynecomastia, or the development of breast tissue in males. This is due to an excess of estrogen being present in the body, due to a process known as "aromatization", whereby androgens like testosterone are converted to estrogen. This excess estrogen then finds its way to receptors in breast tissue and stimulates them to start enlarging. Most experience itchiness of the nipples, followed by pain, followed by a small "lump". The most common ways to treat gynecomastia or "bitch tits" is to use a estrogen receptor antagonist such as Nolvadex or an aromatase inhibitoir such as Arimidex, Aromasin, or letrozole (Femara). All of these compounds can be used with some degree of success; although I've had the best results when using Letrozole. I recommend 2.5mg daily for 3 days, then 1.25mg daily for 3 days, then 1.25mg every other day for 2 weeks. I have had decent success by injecting triamcinolone (a local-acting corticosteroid) into the "lump" if no resolution is seen using any of the meds listed above. This is somewhat painful but it sure beats surgery. It should be said that surgery is the only definitive treatment. Once the entire gland is excised (if done correctly), it should never recur again."