I had a couple of really dark scars on my leg that only bothered me after I was done with LHR. I got a tattoo to cover them.

Another option was getting skin-pigment tattoo over them (permanent makeup), but I tan really easy so I knew it wouldn't blend right.
It depends what kind of scars they are I think. If it's raised, sometimes dermabrasion will help, or an AHA lotion. Some types can be re-healed by a dermatologist to make them lighter, like using cryotherapy to force the body to redo the skin.
If they're like gaps like stretch marks though, though I'm really not sure. Sadly HRT's fat redistribution has given me a few of those, but at least they're on my upper legs. Anyone have a proven stretch mark therapy?

For smooth scars you can try a full coverage concealer like Duracover or Dermablend, who sell a foundation for legs:
http://www.dermablend.com/leg_and_body_cover.htmlI see "airbrushed legs" options in drug stores now, which might be an option, but I've never tried them.