I'm on a Sprint SERO plan, which is their employee referral program: http://www.sprint.com/sero
They opened it up to the public after the iPhone came out. so you can use this address to signup: savings@sprintemi.com
I pay about $34 a month for 500 anytime, unlimited n/w (nights start at 7pm), unlimited data, and unlimited texts.
Unlimited texts aren't part of the plan, but if you ask for it after signing up they should give it to you.
I've never had a problem with Sprint's network.