I am looking for a PHP developer who can developer a script so that, a user can enter in a field(textarea) and upon submission, have the message sent to certain cell phone as a text message.

That is it in a nutshell. As for price, I'm flexible, but the maximum I'll pay is $200.

Im not sure if this is what you are looking for :

http://forums.digitalpoint.com/showthread.php?t=471698&highlight=sms

10$ for an SMS text messagin script.

let me know if you have found something, if not we can talk.

I can do this as well, what countries are you looking to sms-ing ?

AT&T:

AreaCode+Mobile@mobile.att.net
Verizon:

AreaCode+Mobile@vtext.com
Nextel:

AreaCode+Mobile@page.nextel.com
T-Mobile:

AreaCode+Mobile@tmomail.com
Sprint:

AreaCode+Mobile@messaging.sprintpcs.com
Cingular:

1+AreaCode+Mobile@mobile.mycingular.com