I have ankle holsters for my PPK, my model 60, and my 342ti. I recommend them highly.
My advice, however, is to get a good ankle holster (ie, one by Galco). Definately one with padding. Don't go for those elastic ones with the velcro tab. They're junk and the gun will dig into your leg.
Also, don't try to use it with a big gun. Keep it small.
While some say it is slow, I'd rather have a slow draw than no draw. As I can't always wear a jacket, the ankle holster goes with me when no other gun can. Also, if you're sitting, the ankle holster is as fast or faster than other draws.
Hope this helps.