Zinio is a mobile reading application, which features popular magazine subscriptions of which you will be familiar, from Esquire to Nuts to T3 to Digital Photography, loads more.
If you register on their site, they will email you a free $25 credit within a few days. There's nothing in the registration process that tells you about this offer, but I signed up and got my free credit within about 2 days.
I've been downloading a few free mags to my iPad to read on it there, to spend the $25 credit. I got an edition of Wired, iPad & iPhone user, & Cosmo Bride!!