I was looking for a web site that generated tones to be used for tuning
instruments, and found something even better, an online tuning meter that hears the tone you play and tells you if it is in tune.

tone generator page here:
http://www.nch.com.au/tonegen/index.html

perfect pitch tuning aid here:
http://www.nch.com.au/tuner/index.html

does anyone else have any other tools that they have found online?

there must be a place where you can hear an A 440 tone...