Linden Lab have officially updated the Terms of Service today: http://secondlife.com/corporate/tos.php. When users log into Second Life they will need to agree to the new agreement.
As of October 6th 2010:
October 6, 2010 – With the closing of Xstreet SL, we have consolidated our marketplace terms in the Second Life Terms of Service and the Second Life Marketplace Fee and Listing Policies. We have also updated our Policy on Third-Party Viewers to clarify our requirements for connecting to Second Life with a third-party viewer and for participating in the Third-Party Viewer Directory.
Here is a snapshot of the new ToS:
SL Bug Alert:
If you are using the Imprudence Viewer, then check out Bug with SecondLife TOS acceptation blog post for the latest updates. There are workarounds and will be fixed ASAP.