if it's within the first 30 days of purchase, they'll look for you to bring the phone back into the store & ask you questions round a bout to catch you off guard and reveal it's still in your posession.
if it's after 30 days of purchase, you're dealing with the Asurion Insurance company. from what i've heard--Evo's are still on backorder in most of the US (see post on this forum "Asurion Update" stating he was told 5-7 days, not guaranteed any longer). it could be a while--hope you've got a backup smartphone to hold you over.
why not unroot & send in the phone to Asurion? (you keep the battery/cable/MSD card, etc) b/c they're going to black-list your current Evo's ESN & make it unuseable on a cellular network anyways.
or are you looking to keep it just to have two? (i don't blame you--that sounds like a rather enticing scenario)