Hi !
Well I have not done this ..., and Don't know about PDU thing.., But had read an article in "elektor-electronics" on SMS through Microcontroller for some process control application. May be U'll get some info there. It's Jan Issue of elektor-electronics in UK, but I guess it was in Feb issue here in India.
Try this link "http://www.elektor-electronics.co.uk/ln/detail...e0102u.htm"
Regards
Vignesh baliga