Ubercart Legal Agreement

This module allows you to assign one or more legal agreements to a product. The customer must then accept the legal agreements to complete the checkout process. Once the customer has accepted the agreement, further checkouts can proceed without additional prompts to review and accept the same agreement.

A record is kept of the date/time that a legal agreement was accepted.
Each legal agreement automatically expires after a period of time (default 12 months), forcing the customer to review the agreement upon next checkout.
If the legal agreement has changed since the customer last accepted, then the customer will be prompted again to accept the legal agreement.

Similar modules are:
Ubercart Node Panes, http://drupal.org/project/uc_node_panes
Ubercart Terms of Service, http://drupal.org/project/uc_termsofservice