I've been carrying an LCP in an ankle holster for four years now. I picked up a cheap Uncle Mike's nylon holster to do until I found something better, and I've been using it ever since. The Uncle Mike's holster is quite bulky, but it turned out to be a non-issue.
There are two basic types of ankle holsters: the kind with the strap that uses your calf to hold them up, and the kind that ride on top of your shoe. Some of the latter have optional calf straps.
The other two basic types are 'right hand' or 'left hand.' Ankle holsters are designed with the idea that you'll wear them on your gun hand side, use your off hand to raise your pant leg, and then jam your fingers between the gun and the holster or your leg until you can get a grip on it and pull it out. The gun is carried with the butt pointing to the back.
I've found it *much* more convenient to use an opposite-hand holster that lets the butt point forward.
One of the things I didn't like about the Uncle Mike's holster was that it had elastic straps with Velcro. I wanted D-rings and buckles. However, I now have a medical condition that makes my legs swell during the day. The elastic turned out to be quite useful.
The little LCP collects an *amazing* amount of dirt riding down there, even in the winters when I'm not mowing the yard. The holster is machine-washable. I use the air nozzle in my workshop to blow the crud out of the gun and use graphite as a lubricant. Silicone wipes help keep rust away without leaving an oily surface for dirt to collect on.