How to do VGA-programming in protected mode?
First of all my future OS assumes that VBE 2.0+ is supported. It is checked at boot-time. Ok. It is supported, but what next? As I understand the specification, only functions 5,7,9 can be called from PM. I can get possible video modes at boot-time, then enter it, and, finally, enter PM. But how to change video modes when already in PM? Or what steps should be done at all?
Maybe you know some good tutorials on this topic?

i think you should call 16bit interrputs, eg. load 16bit interrupt vector table, switch to 16 bit mode and call something from there.