hi, i have been playing the alto for 7 years now. I play ina jazz band and a peice we were recently gicen has a high G written in, i think this can only be achiven by using harmonics, can anyone help me?

Are you talking about the G above the staff? http://www.wfg.woodwind.org/sax/sax_alt_4.html Check out this fingering chart and see if those help you out.