I recently bought Photoshop CS5.Am I entitled to free upgrade to CS6
The free upgrade offer is for users who purchase(d) CS5.5 Suite or component products through Adobe.com after March 26. Since Photoshop did not have a CS5.5 release (but it did get a 5.1 designation inthe CS5.5 package), I would presume that a purchase of Photoshop CS5.1 on or after March 26 would be eligible. See http://store.adobe.com/store/en_us/popup/offer/cs55_cs6_faq.html
Note that the offer might not be valid outside the US, however.The FAQ says the offer is also valid for purchases at other resellers, but does not seem to provide details about how to get your coupon. If either of those apples to you, you might want to call customer service for your region.
It’s valid worldwide however I would say that March 26 date is carved in stone since this was a brand new policy. Adobe has never preannounced free upgrade prior to actually announcing the product.