To be simple, Game Engines are a set of classes that makes Game Development simple. For example, we can call our Midp 2 Game package as a game engine. Its a very simple engine which has very basic classes. And we also have m3g in many devices which support basic 3D stuff. There are very few Game Engines available in the market and not any Opensource engine till now. (As of my knowledge)
Our company, Smackall Games work only on J2ME as of now, and a separate team for Brew is coming up. We are particularly into mobile gaming and other entertainment softwares for mobile
I have sent you a personal message here in this forum, requesting your resume. If possible send me a few sample codes for a game in any language or platform.