If you're looking for CAT B30 compatible apps, you can try these:
opera mini 4.5, UCbrowser9 - probably the best web browsers;
moby explorer, bluftp - file explorer, compressor, text editor;
xcalc - scientific calculator;
adobepdf - pdf viewer for small files only;
I've spent a lot of time downloading and testing. These apps work. You can find them on phoneky.com