Hullo Ioannis, probably u needed details,my code is below,am using pic16f877,
code:
DEFINE OSC 8
DEFINE HSER_TXSTA 20h
DEFINE HSER_RCSTA 90h
DEFINE HSER_BAUD 9600
DEFINE HSER_CLROERR 1

PushButton var PORTB.0

Main:

IF PushButton = 0 THEN SMS

goto main

SMS:

HSEROUT ["AT" ,13,10]

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

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

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

HSEROUT ["AT+CMGS=+256782277658"]

HSEROUT [13,10]

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

HSEROUT ["BUTTON HAS BEEN PRESSED!"]

HSEROUT [26]

HSERIN 15000, SMS, [WAIT("+CMG")]

HSEROUT [10]

end