Hi Tiram
Yes, it's perfectly possible to fly as Cabin Crew and then go for the pilot thing. I don't honestly think it'll increase your chances of becoming a pilot though (or decrease the chance either). That depends on how committed you are, and your aptitude to fly. In that sense, anyone with the commitment and aptitude could become a pilot (subject to availability!)
As for the experience, it'll definitely give you loads. You get to speak with the guys & gals up-front, ask loads of questions, see loads of nice views, speak with the despatchers, look at loadsheets etc. etc. You might even get to stay overseas in hotels, although that depends on who you fly with. You'll be popular with Cabin Crew when you start flying as a pilot, cause you'll know exactly what their job is like, and thus treat them with respect, especially if they're having a bad day!
The only thing I would say is that you should think a bit about the rosters you will be flying, and how tired you might be feeling after a flight; at my airline, we fly 3 earlies (anything from 0400 to 0700) then 3 lates (anything after 1200). It's up to you to decide whether you'll be up to some serious studying after flying, as sometimes you can come home feeling knackered. On the other hand, you do get lots of time off, and this time can be used to hit the books.
If it's any consolation, I'm currently studying the theoretical part of my PPL course and flying as Cabin Crew in my spare time!
There are loads of airlines recruiting; easyJet, Virgin, BA, BMI, Bmed. Take your pick.
cheers