Amateur Radio operations are subject to the Part 97 rules.
The Amateur Radio Relay League has posted them at their web site. It is an excellent reference.
Check out this ARRL FAQ ENTRY regarding cross band repeating. This link is provided by the webmaster and does not necessarily represent any position held by the DRL its officers and members. Thanks go to Shawn Shenton, KC�LZE, for digging that reference up at the ARRL website.