iPod Touch Classroom Launch

Greetings!

Podcasts such as Teachers Connecting and Two Tech Chicks have convinced me to invest in a set of iPod Touches for use in my 3rd grade, self-contained classroom beginning this fall. I'm very excited about integrating this technology into my instructional arsenal but could use some help with the following:
1. While the iPods will be used for supervised centers or small groups this is a personal investment that calls for some security. Does any one have any ideas on where to find cable locks for iPods?

2. The Apple Apps Store looks very impressive and I've seen several things I think will be useful to my learners. I would like, however, any ideas experienced users might have for educational apps they've found particularly successful.

3. General tips on iPod center/small group management would be welcome including introducing the technology to students.

Thanks!