touchdown for exchange is pricey but worth it, IMHO https://play.google.com/store/apps/details?id=com.nitrodesk.droid20.nitroid&hl=en
haven't ever used it for exchange but K9 Mail is free and open source https://play.google.com/store/apps/details?id=com.fsck.k9&hl=en
haven't ever used it for exchange but K9 Mail is free and open source https://play.google.com/store/apps/details?id=com.fsck.k9&hl=en