Guess my correlation

This website runs Java. Firefox might be best. 10 minutes with this site and your students WILL understand correlation.

Websites for stats

This source lists tools by statistical topics.

NCTM Core Tools

Click on "downloadable suite".

Lock5 StatKey

Data is pre-loaded for a textbook. But you can click on Edit and insert your own.

Statcrunch

This is an awesome site. You need to get a free instructor's account. 

Tuva Labs

This site has awesome data sets pre-loaded. Very real world. Very applicable.

Casio Education Guides (including stats)