Coinapult is a great free online wallet that you can use on your mobile devices but with no specific dedicated app. That said the wallet does allow a host of features such and methods to transfer your bitcoin as seen below. Probably one of the top apps for breaking into the emerging markets of the unbanked e.g. Africa.
Send bitcoin transactions to a bitcoin address
Send bitcoin via email
Secure storage for your bitcoins
Track your transactions history
Easily customisable Invoices