I have a good friend that I speak to ona daily basis who is a "priestless" old believer, but has,through providence, realized that there can be no Christian Church that denies the mysteries, especially the Eucharist. He will more than likely be joining the group in Pensylvania, but is soon to be trying to 'convert' his family and friends to "get the priesthood".
Anyway, his group is not in communion with anyone but the rest of the priestless old believers, and any of the other old believers are pretty much in communion with ROCOR. The OB's are pretty reluctant to do anything resulting in communion with the rest of the 'apostate Orthodox' (everyone else)and typically won't have any dealings with them at all. the are very close knit and any form of change is met with alot of antagonism.
Theologically, everything is pre-Nikonian as stated above, and everything after the Stoglav or 100 chapters council in Russia is denied as heresy and abominable. They are very very rigid and place salvation on most things that are customary or ethnic in most of our churches. Say for instance, beards. Men grow them and never shave them. It is an abomination and offense to God to shave one's beard. Women's head coverings must not be tied around the chin, but pinned. Coffee is considered as an idolatrous offering, and is almost the anti-Eucharist if you will. But what is funny, is they drink Braga(a berry alcohol) by the gallon.
They feel that at the time of the Schism( and they have no qualms calling themselves schismatics) the Constantinopolitan Church was no more because it had fallen into heresy by communing with Rome at Florence. So for them to try to bring in Greek forms and customs at the time, was basically like unto bringing in heretical Latin customs. At the time, it was considered to be the last days, and they awaited the parousia. People were encouraged to self immolate themselves in great numbers as a baptism of fire, as they felt it was a form of matyrdom.
I can babble for pages, but I suggest going on Google or whatever adn searching for:
Freedom for an old believer (a 'autobiography' y one)
Old belivers of Oregon/woodburn
Old Believers Priest Avakkum (spelling might be bad)
Old believers of Estonia
Old Rite Russian Orthodox parish pennsylvania (this is the master Russian Iconographer Fr. Theodore Jurewicz's parish)
etc...
hope it helps
photi