0muon321 has pointed out that my last post is incorrect. He is quite right. The equation I was going for is E = hc/(lambda).
So, let's say we have a proton, and it is at rest, and we use the equation λ=h/p to find it has a wavelength of 0 because it has no momentum.

Actually there is a problem on this line. (lambda) = h/p runs into a problem when v = 0. (lambda) is undefined for a particle at rest, due to p = 0.
Dan