Yes.. they are indeed different.

The following is from the url I posted above:

Airlines have already banded together to take back sales from others' Web sites. Last year, Delta Air Lines, United, Northwest and Continental announced plans for a Web site to sell published-fare leisure tickets, competing with established sites Travelocity.com, controlled by Sabre Holdings Corp., and Expedia.com, controlled by Microsoft Corp. Initially dubbed T-2 — short for "Travelocity Terminator" — the venture now is called Orbitz. American has since joined the venture, which is expected to launch in September. About 25 other airlines have signed up to make tickets available on Orbitz, including special Internet fares.

The Justice Department is investigating whether Orbitz is anticompetitive. Orbitz officials say it isn't, because it has independent management and its search-engine technology is neutral.

Hotwire isn't worried about Justice Department scrutiny, says Mr. Peterson, the CEO. That's because Hotwire's governance resides with Texas Pacific and Hotwire's board, which includes no airline representatives. The founding airline partners won't receive any favoritism over other carriers or travel suppliers that sign up later, he says. Hotwire management will decide which vendors to allow in.