Adobe has decided to modify its previously stated upgrade policy for its Creative Suite products, which includes, among other things, Photoshop. In December Adobe announced a policy that would basically require you to upgrade to Photoshop 5 or 5.5 to qualify for a discounted upgrade to Photoshop 6. This policy was, ahem, not well-received by Adobe's customers.
The new policy is a lot like the original policy: You still qualify for a discounted upgrade price if you own CS versions 3-5, at least until December 31, 2012. (What happens after that is anyone's guess.) The difference is that the upgrade pricing is tiered. The more recent the version of Creative Suite/Photoshop you own, the greater your discount. Feel free to click this link for more details.
Isn't it nice to know that even companies as big as Adobe listen to the voices of their customers--or should I say "howls of protest?"