I found
http://www.getjar.com/software/ quite useful for free / demo apps
I did notice opera (mini) on there but I suppose you can find that on the opera website too. Games I found on there tha work on my W850i - pipes, chess (by cellfun), bombsweeper, solytare. There were some applications but not much that seemed useful or free really.
just make sure you've selected the right kind of phone/screen/etc and that you do run a quick virus check on them (I grabbed a bunch of the games and one file out of the 20 or so was flagged by AVG with something. Might have been harmless like the cd-tray eject "joke" but I deleted it without doing any real further looking.