Can I start to study for the MCAT now, and what are some good books for MCAT prep?

This is the best book out there for the MCATs. Good luck!

http://www.amazon.com/Kaplan-2007-2008-Premier-Program-CD-ROM/dp/1419541978/ref=pd_bbs_sr_1/105-8665608-0168417?ie=UTF8&s=books&qid=1183647291&sr=8-1

Studying  for the MCAT right know, but basic science knowledge is needed (bio, chem, physics, org chem, and verbal)
As you complete them, you can start studying them, or you can study as you go (if are going to take bio this year, just study MCAT bio as you go)

understanding the basic science courses in college will make it easier to prepare for the MCATs, so my advice is to pay very close attention in these classes

Sure! I've been studying since I was in high school lol it's never to soon to start.
I would recommend to take as many practice tests online, and just take as many biology, physics, and chemistry classes as you can!

The MCAT isn't really a type of exam you can "study" for.  It's a logic-reasoning exam.  The knowledge required for the MCATS will be obtained through your science courses.  You can try studying now (I used the Kaplan book), but it probably will not help much until you fully understand the basic principles of the material covered in the book.  

Personally I would start after you've had an intro to biology course, microbiology, genetics, organic chemistry, and physics.  One approach you could take is to start studying for those sections after you take the respective course.

Jessica, from the looks of that picture of you, I think you probably need me to come over and help you with the anatomy lessons.

Yes study now but one advice that is rarely given, you should take your MCAT RIGHT after you finish Organic chemistry, trust me this will help you out tremendously!