I think there are no less than three organizations that claim to be carrying on the IRA torch. there's also INLA, a republican militia. I've tried finding more contemporary information on these groups' status, but its hard to come by and a lot of it is conflicting.
it seems to come and go though, I guess it all depends on the social and political climate of N. Ireland. Activity, likewise, comes in spurts.
But I think RIRA's (Or was it CIRA? fuck it, I can't keep all these groups straight) leadership was recently gutted so they may be struggling now... One thing for certain, though, is that irish republicanism and its militant arm are probably not going anywhere anytime soon.
I've also read on the web that some republican organizations are amalgamating, so there's that as well. Like I said, though, there's tons of conflicting information out there.
Also, a while back the BBC (I think?) put out a series of documentaries on The Troubles, examining it from both sides of the argument. You can find 'em all on youtube. here's the first:
http://www.youtube.com/watch?v=zqmbWuaTJvEthe rest'll be easy to find from there.
