Steve,
I personally wear a "skin suit" made specifically for scuba under my wetsuit. It's basically a spandex suit that's smooth on the outside & either insulated or not on the inside. The extra insulation helps if you're diving in colder water & the suit makes getting into & out of my wetsuit really quick & easy. If I remember right, they can be had for $100 or less depending on the insulation... (Mine was a gift, so I don't really know the prices...) If you don't want to invest in a skin suit, I have heard that some people make up diluted solutions of either hair conditioner or liquid soap & water to squirt inside their suit & make it easier to get into. Hope this helps.
JP