Yes, Lipton's is gluten-free. You can always call the 1800 number on the box if you're unsure.
Here's the tea listing from the Wheaton (Chicago area) Celiac Support Group.
Tea
Arizona (800 227-3775): all (2/04)
ASHBYS of London Teas (800-334-6485) (08/04)
Big Train Chai (800 682-5047) (www.chaitea.com): Spiced, Vanilla, Raspberry,
Chocolate, Green...