BigMatt has got most of it spot on.

You can of course take the tax free cash, which is usually 25% (some older schemes can be more). You can then put the rest into what is called drawdown, but not actually take it until a later point. Bear in mind that once you have taken your pension, the 75% balance is subject to 35% tax in the event of your death. In fact, the highest tax charge on a pension is 82%!

You need to use an IFA to utulize the "open market option" as it's rarely better to stick with the same company.

Brian