One thing I have done with pretty good success is wrap the rim with duct tape to protect the tube.
Is the tube you're using the correct size? If it's too small, it'll split at the seam. The recommended size for my 65's tires is a little small, went through a couple before I went up one size, and haven't had a problem since. The only good part is once the bead is broken once, it's pretty easy to break again.