Hi Tina,
I'd recommend that you visit Erin's blog as she has a lot of information there in various articles. She and Steve have also just done an excellent podcast that covers the topic of spirit guides.
I recently also did a series of articles on developing a relationship with your spirit guides. Part 1 is available at
Woo-Woo Wisdom: Developing A Relationship With Your Spirit Guides (Part 1)
and Part 2 at
Woo-Woo Wisdom: Developing A Relationship With Your Spirit Guides (Part 2)