Sprint is offering an instant $125 credit to anyone who moves their number to Sprint, and buys a smartphone like the Samsung Epic 4G. That's a pretty good deal. I've used Sprint for years and my calls don't drop and they have good coverage. All they need is the iPhone and they could compete head to head with everyone else.

Just bring your number from another carrier to Sprint and activate a smartphone, like the Samsung Epic™ 4G, on a new line and we'll give you a $125 service credit. Not ready for a smartphone? We'll give you a $50 service credit when you port your number from another carrier and activate one of our other fabulous phones. Either way, you win.

$125 service credit per line for each smartphone
$50 service credit per line for other phones

As mentioned, if you don't want a smartphone they'll give you $50 for moving over. Not bad.