This Indian startup is only a few months old, and it is just now beginning to get the attention it deserves. It offers similar features to Onswipe and could potentially blow Onswipe out of the water. I'm looking at the demo site that Mobstac made for me, and while I don't like some of the design elements there are number of subtle details that are nice. I like it enough that I'm willing to let you see what my site looks like:
There's an iPad and an iPhone version, and if you visit from a desktop browser you will see the iPhone version. You can also see the iPhone version from any Android tablet; Mobstac is repeating OnSwipe's mistake in ignoring Android. This is a paid service, not free, but "you get what you pay for". I was set up with free account, so that does bias me. But this is definitely worth deeper look.