sms messenger for pc

is their a client program out there that will allow me to send sms messages to a cell phone right from my pc

without the use of a mobile number
i can't sms message from my mobile phone i can't afford it, the point of all tghis is to sms message people without buying the services for a cell phone, i appreciate the help

for some additional imformation
the persons that i am planning to send sms messages to uses CRICKET wireless and when i sent them sms messages through my email they couldn't respond (well they replied on the phone and the phone says that the message went through and i checked my email the message wasn't there)

also would be cool to set up an account becuse when i send through email my names doesn't show just my email address which no none who knows me is familiar with

still appreciate the help thanks