Switch between Edge & Wi-Fi? 3G

[aklmtnbkr]

Hi - Is there a way (or an app) that allows you to switch between Edge & Wifi at ones convenience? My mobile provider is very expensive when using the Edge so I had it blocked for now on their side (& I just use my personal Wi-Fi connection) but once I leave my house, I cant use MMS etc? So was hoping to find a way to switch to Edge at my convenience?

Thanks

[blkcadi]

install SbSettings in Cydia