Make sure you take some time looking at Kai Axford's recent blog post. As Kai reminds us, there are some new rules that went into effect on December 1st, 2006 that impact when and how email may be deleted. Kai links to some other articles on the subject. Check it out.
Thanks for the Technet event today, it was very helpful. Getting a free ISA 2006 server was pretty sweet as well.
As far as the electronic media retention laws,
this is the link to the US Governments site explaining all the details and without the 3rd party advertisement.