there is no way for real OTA downloads with Opera so you have to find jar/jad files and install them manually. I was in St.-Petersburg few weeks ago and had no problems with Opera at all but haven't tried MMS though. Try GMail application Blackberry Blast!:: Gmail Mobile for Blackberry Released
but I'd recommend you just use Opera..
There is no any kind of support for BB's from MTS, Megafon of BeeLine and you even can't use all settings for GPRS from their web sites except APN name which is enough for Opera. If MMS APN is different from internet access APN you won't be able to send MMS.
Actually I wonder how many people in the sity have BB's at all)) I will bring one Pearl for sale since it is just sitting on my table right now with no use...
PM me if you have questions and prefer Russian for communication