There's hundreds of ebooks you can waste money on. However if you really want to learn, just setup a simple campaign with a $5-10/day limit and learn it as you go. If you keep that that budget you'll only spend about $200/month and you'll learn more than any of those ebooks could every teach you.
Google provide loads of information for their adwords progarm - from the main learning centre https://adwords.google.com/support/aw/bin/static.py?hl=en&page=learningcenter.cs&ctx=go&hl=en_US and their youtube channel http://www.youtube.com/user/GoogleBusiness 98% of the ebooks and courses for sale just rehash this - don't waste your money - use all the resources from google
Learning as you go is always good but set your budget low. When ever I need help I look up youtube to see if anyone has made a tutorial.
I do provide program for PPC, check my sig. But in the end it's up to you. Experience is the best teacher in PPC.
PPC is a trial and error. I've work on a campaign before that gets me an average of 10k conversions a day on Adwords alone for a year. Before I attain that, weeks of jumbling words, rewriting and adding ad variations, improving landing page... etc...
I wrote an ebook that is a good starter guide. I was going to sell it but the industry of ebooks is just too packed so I dropped the idea. Still, I have it, if you want it, just send me your email via PM and I'll shoot it to you. No strings attached.