I'm 2.5 yrs out from my first IMRT which was directly to the mouth/tongue and my saliva is actually decent these days. I still wake up feeling like my mouth is a dry lakebed but it gets going during the day. I'm not even sure when it happened, I've just noticed recently that it's not too bad these days. My second round of Rad was in summer 07 but it was only to the neck, nothing towards the mouth.
I still have taste issues (sweets taste terrible) but that's another story....

Age 41 - Stage 2 SCC tongue Dx 2/06. Cisplatin x3, IMRT x35. Mets to neck node discovered 7/07. RND 40 nodes removed, margins not clear. Cisplatin, Taxotere, 5-FU Fall 07, then IMXT/Erbitux for 7 wks. Inoperable mets to both lungs and pleura Dx Oct'08. 4 cycles Carboplatin, Erbitux, 5-FU so far.