Digital Point has a good FAQ on Google Adwords. http://forums.digitalpoint.com/showthread.php?t=200367 I am not sure on where to learn about general PPC though...
After you read through and understand the concept of it. The best way to learn is to your experience, like signing up a google account. Only 5 bucks to begin with.
Why waste money trying it when theres tons of information out there on it. Start with DP, read the usefull stuff on here then move onto the Google adwords learning centre. There you will find the entire syllabus for the google adwords exam. Maybe once you have read all that you could start a few small campaigns. You might as well chuck your money in the bin if you try before learning as much as you can.
i have some theoretical knowledge but i don't have practical..but i am very much interested to work practically but i yet not get any chance.
Have you checked www.feedurbrain.com ? Just Check it, and u won't take more than 20 secs to find out it worth joining/reading what they got. Hope I could help