If I would be you I would start with Jerry Lodriguss' Catching the Light. After understanding that book, I would move to Ron Wodaski's "The New CCD Astronomy". The only catch is that this book is no longer in print but I have it from a very reliable source that if you join the Yahoo group and ask him nicely he would give you the pdf version.
It's an AMAZING book and you would understand the WHY not only the HOW.
For intermediate processing skills, the next Jerry Lodriguss book is gold. There are many more out there. I've tried to stay away from those that do not apply to Photoshop but that's not to say that you should too.
Scott Ireland's book is another well respected one. However, I have my reservations about it, mainly from the fact that it came into my possession a little too late. Most of the techniques presented in the book are included in the Noel Carboni action pack.
The last on my list would be the second Ron Wodaski book - ...Astrozone... which is held in high regards and judging but how good the first one was I have no doubt about it.
Good luck and welcome to one of the most expensive hobbies that you could have come across.
