This worked like a dream. I immediately put reMail on my home screen and was happy. At least, that was, until last week when I read that Gabor Cselle, reMail's creator, announced that the app was being put out to pasture, and was immediately being removed from the App Store. Google both bought the app and hired Gabor to be a Product Manager on the Gmail team.
As a nice gesture, Gabor decided to keep supporting reMail until the end of March and make the two in-app purchases free. Along with IMAP support, you could also buy the option of having it work with Rackspace email. And thus started the conspiracy theories. Techcrunch surmised that this could be another shot over the bow in the Apple-Google smartphone war, and that Google bought the technology to kill it off, so Apple couldn't buy it first. There may be something to that since reMail is arguably a better mail app than the one that built into the iPhone.
On the other hand, it may be that Google, seeing a widening of the search market, wants to build reMail's functionality into another product. It would be foolish, in my opinion to not do so. Google has worked with Cselle before as part of the Gmail team and knows what he can do. With reMail as part of the bargain, he's more important to them than during his earlier tenure.
There is a rumor floating around that someone has reverse-engineered reMail and will release it as open source. This could be interesting and may change the game, but it may be just a rumor. Whatever happens, it'll be intriguing to keep your eye on the evolution of mail apps on smartphones, and to learn just what Google has in mind.