As I said in another thread my salary has increased 96.5% since October 2006, so from my perspective I am not seeing a decline in salaries.
While I don't think there will ever be a general shortage of pilots, there certainly will be occasional shortages of experienced pilots. This has occured twice in the last decade or so that I have witnessed, 2000/2001 & 2007/2008. I suspect we are about 18-24 months away from a similar situation again, once QF/Jetstar get their intra company movements/wranglings sorted out.