Thankyou Ioannis, currently its pic16f84 available for my project and in my country its hard to get access to microcontrollers so i have to just utilize it.
I have replaced HSERIN/HSEROUT with SERIN/SEROUT but still generating errors,probably i have change something again;
After changing this is the code:
DEFINE OSC 4
DEFINE HSER_TXSTA 20h
DEFINE HSER_RCSTA 90h
DEFINE HSER_BAUD 9600
DEFINE HSER_CLROERR 1

'Setup the names that will be used throughout the program
PushButton var PORTB.0 ' Setup the name PushButton to mean PortB input 0

Main:

IF PushButton = 0 THEN SMS 'If button is pressed then run the SMS routine below

goto main ' however if the button is not pushed then just go back to the Main
' routine to wait for the button to be pressed

SMS: ' this is the SMS commands routine in order to send an SMS

SEROUT ["AT" ,13,10] ' send AT to modem followed by a CR and line feed

SERIN 5000, SMS, [WAIT("OK")] ' now wait for 5secs until OK is received however
' if it is not then goto the SMS routine again

SEROUT ["AT+CMGF=1" ,13,10]

SERIN 5000, SMS, [WAIT("OK")]

SEROUT ["AT+CMGS=+256782277658"]

SEROUT [13,10]

SERIN 5000, SMS, [WAIT(">")]

SEROUT ["BUTTON HAS BEEN PRESSED!"]

SEROUT [26] ' this is ASCII for Ctrl+Z of which completes SMS sending

SERIN 15000, SMS, [WAIT("+CMG")] ' then PIC should receive +CMG from modem

SEROUT [10] 'ascii code for a line feed

end

regards
dumato