I agree with the pilates recommendation. it helps a lot! I taught a pilates class for two months about 4 years ago. I also found it was great for improving balance especially. I also agree that physical therapy is vitally important and good PT of real value.
I got a "foot up" device for improving toe lift and that helps some. I also ordered but have not recieved yet a device that lifts the whole leg called a hip flexion orthosis device found here http://www.footdrop.org/leg_lift_guarantee.htm
and a picture of another UK version here http://www.musmate.co.uk/
It is essentially a bungee cord that comes off of a belt under your clothes that gives you an extra boost to your leg and foot. I'll let you know how it works when it comes. The fellow who makes the US one has had MS for years and has used this device for 12 years to walk. He's quite a loquacious fellow! There is also a for prescription version--also for many many more dollars availalbe as well which I can't find the link to. I have had foot drop on the right for several years, and last year an old lesion had developed a black hole so I am assuming that is not going to go away no matter what unless we get regenerative strategies soon, but I agree with a Sharon that one really important thing is to avoid the kinds of approaches that make you stop using the limb in question unless it is already completely paralyzed. But for me even the little foot up thing has helped a lot and I can walk further, longer, and more safely, super important.
Like all things MS it is challenging!