Hi Fire3,
You won't go straight into the captain's seat on an airliner. You'll more likely start of as a first officer in the right hand seat.
The minimum licence required is a JAA CPL/IR with ATPL knowledge, otherwise known as a "frozen ATPL". Most airlines will ask for an MCC certificate as well.
There are two methods, Integrated and Modular.
Integrated you're look at somewhere in the region of £55,000 to £70,000 depending on school.
Modular is somewhere between £30,000 (you'll be lucky though) to around £50,000.
This assumes you don't have to pay for your own type rating (Boeing 737 etc) which costs something like £20,000 to £25,000 extra.
These are VERY ROUGH figures from the top of my head.
Hope this helps.
Charlie Zulu.