I've tested several push messengers like Ping! and Pushme.to over the past few days. Finally I tried Push Inbox which offers the best feature set for my needs: web > iPhone, mail > iPhone, iPhone > iPhone and it's possible to even answer web und mail sourced messages from my iPhone if a sender mail address is given. Up to 10 aliases like myname@getpushinbox.com can be used. Lifetime subscription is 0,79€ or 0,99$ at the moment. The Push Inbox app itself is free.