What is a B Broadband Router and whats its difference between other routers like a G Router?

the letters refer to the wireless specification used. in long for it is 802.11b or 802.11g and the latest one is now 802.11n. the farther along in the alphabet the faster it is basically. you do need to have a card capable of those speeds to take advantage of it though, for instance, you could get an n router, but if you only have g cards for your computers you won't see any speed difference than if you had a g router. They aren't entirely intercompatible though they often tend to be, just look at the specs on whatever you get to make sure it is compatible with what you have. generally these days everything is compatible with g.