Technical problems

I hate this. We've got a good plan for our game. I'll write about that later, but currently I'm just bumping into technical problems. Well, for a start I was planning on using a richer library than pygame to start with. Pygext looked good for this purpose... but then plans changed and I realised I'm really going to need a tile engine, so I switched to pgu... only to realise that I'll need some lighting effects... figured that sort of thing would be better to do in OpenGL, so I made my own little rendering hack for pgu... but seriously, I'm not too experienced with OpenGL and I can't figure out how to do lighting in a 2D scene. Basically I would like to assign each pixel on the screen a lighting value. Tried to blit a fullscreen alphablended "lightmap", but that's too slow... I guess I either have to find an alternate way to do that or try to optimise it to work on single tiles instead of the whole screen. Then I might get away with not updating the whole screen all the time, which would be good. I'm going to give lighting effects a rest for now and try to implement some gameplay instead. Any tips on doing 2D lighting effects, OpenGL or otherwise, would be appreciated.