To steam you need a clothing steamer for best results. I have seen it done with wringed microwavaved rags but have never tried that method myself and cannot attest to its effectiveness. Leather is a weak material and requires TLC. Its surface is only "skin deep", scratches easy and adsorbs fluids like a mofo. Sometimes by remosturizing (steaming) you can reduce the apperance of wrinkles.
Vynil is sowhat better as it does not adsorb but nothing beats coarse synthetic weaves for durability.