Just wondering if arduino is able to recieve an sms and automatcaly send it to a printer. And also do auto reply?
Yes, you need : 1) a GSM shield - e.g. - http://www.sparkfun.com/products/9607 - and - http://www.sparkfun.com/datasheets/CellularShield/SM5100B%20SMS%20App%20Note.pdf -
2) a serial printer (other printers are more difficult) - e.g. - http://www.sparkfun.com/products/10438 - but you probably can find some on eBay too
3) an appropiate sketch - that will take quite some puzzling but it is done before
You can implement GSM part much easier. USB Host Shield and an old phone will cost quite a bit less than GSM shield and won't take precious serial port . You can also reuse both shield and phone when you get bored. See here -> http://www.circuitsathome.com/mcu/programming/interfacing-arduino-to-a-cellular-phone