You have to be careful when splitting the coax. The splitter needs to support the higher frequencies (older splitters didn't). Also, if you're going to a 4 or 6 way powered spliter (amp), then make sure it's bidirectional. What I used to do is split the caple with a simple 1-to-2 spliter (one connection to the internet, the other to my 4 way powered splitter). That way my internet didn't go through the amp, and the 4 way amp would boost the signal to the TVs.
How many tvs?