The 45 ton Bulava ICBM is slightly a slightly modified version of the Topol-M. The Bulava is a little shorter, to fit into the missile tube, and thus has a shorter range of some 10,000 kilometers. Bulava has three stages and uses solid fuel. Currently, each Bulava carries a single 500 kiloton nuclear weapon, plus decoys and the ability to maneuver. The warhead is also shielded to provide protection from the electronic pulse of nearby nuclear explosions. Take away all of these goodies, and the Bulava could be equipped with six smaller (150 kiloton) warheads. But the big thing these days is trying to defeat American anti-missile systems.
Russia has apparently successfully navalized their Topol-M ICBMs (as SLBMs, or Sea Launched Ballistic Missile), and are installing them on two different submarines next year. The new missile, the Bulava, has been tested in a Typhoon class SSBNs (the last of the six to remain in service). These subs, the largest ever built, entered service in the 1980s, but were very expensive to operate, and were gradually decommissioned through the 1990s. The last one in service, the Dmitry Donskoi, was refurbished and had new launch tubes and electronics installed for tests of the new Bulava ICBM. The second SSBN to carry the Bulava is the first of a new class of ships, the Yuri Dolgoruky, which has been under construction since 1996, and was, until recently, not expected to enter service until 2008. But the navy has gotten a lot of extra money of late, and a lot of it has gone to getting the Dolgoruky into service next year. Ultimately, at least half a dozen, and perhaps more than a dozen, of the new Yuri Dolgoruky class SSBNs will be built.