ReMail 2.0 wants to change this. ReMail's iPhone app (iTunes link), which officially launched today, downloads all your email from any IMAP server and makes it searchable, no matter whether you are online or offline. The app, which costs $4.99, includes advanced search functions as well as a very smart auto-completion feature for speeding up your searches.The iPhone's email client is pretty good and with the 3.0 update, it can also finally search through email on your server. To do that, though, you have to be online and you can only do basic keyword searches.
Initial Setup: Slow
The initial setup can take a while, especially if you are trying to sync a very active email account. ReMail says that it can download and index about 3000 to 4000 messages per hour over WiFi, which, judging from our own experience with the app, sounds reasonable. We would definitely not try to run the initial setup on anything less than a WiFi connection.
After That: Fast and Smart
After the initial setup, however, the app is a breeze to use. ReMail's smart auto-completion makes searching for emails easy and you can reply to emails right from within the application. The real game changer here, of course, is that you can finally search all your email from the iPhone, even if you are offline. What really makes the app stand out, though, is how fast it can search through your emails, even if you have downloaded thousands of emails.
All of these messages obviously take up space on your phone, but according to ReMail, 100,000 messages will only take up about 500 megabytes. That's a small price to pay for having instant access to all of your email.
One limitation we should point out, however, is that the app only supports one email account, so you can't search both your private and business accounts, for example.
ReMail was founded by Gabor Cselle, who used to work on email related products at Google and Xobni. The company raised funding from YCombinator, as well as from Paul Buchheit and Sanjeev Singh, the inventors of Gmail and co-founders of FriendFeed.