There are two general ways of gaining your commercial pilots licence;
Integrated route or
Modular route.
1)
Integrated Training involves around a year or more of intense study to gain your commercial pilots licence. You study for your PPL (Private Pilot's Licence), IMC (Instrument Meteorological Conditions) rating, Night rating. Then you will complete your studies for your ATPL (AirLine Transport Pilots Licence) theory exams. After having done this you will study for your CPL (Commercial Pilots Licence), MER (Multi-Engine Rating) and finally your IR (Instrument rating). Oh yes, you will also need to complete 100 hours flying between your PPL and ATPL training. Oh and I also forgot to mention the exams, which you will also have to fork out for, which range from about £55 each for the ATPL exams to £1350 for the Instrument rating. (Based on Oxford Aviation Training 2005 prices).
This, depending upon where you train will cost around £60,000.
However, there is a cheaper option.
2)
Modular Training involves you gaining your PPL first, then your IMC rating, Night rating, etc. You can study for these in the UK or you can study for these in the states where the flying is cheaper (although some people may argue about the merits of USA flying training - but that's where I want to do my initial training).
Having completed this training you can then study for your ATPL exams either by distance learning (around a year) or you can go to a training provider such as Oxford to study for the exams in around 20 weeks. You will also have to complete 100 hours private flying before you go on to study for your CPL, MER and IR.
This will cost around £30,000.
But don't quote me, as I haven't begun my training yet myself, but this is what I have researched so far.
Hope this helps?
There are quite a few training providers in the UK, such as Oxford, Bristol, but to name a few. If you do a search of 'ATPL training UK' on the internet, it will bring up lots of options for you. You don't necessarily have to study at a top training provider who ask for large sums of money, as based upon my husband's words (who has completed his studies and is now flying commercially) no amount of money will guarantee you a job in avaition (much to my depression)!