If you sign up to let adobe spam you when you register PSE or if you join for the Product Improvement program, adobe periodically sends emails offering an upgrade price to Photoshop. It's more than the Photoshop version to version upgrade price, but still less than the MSRP. Sometimes if you call adobe sales and ask nicely you can get this even when it's not offered. AFAIK there's nothing on right now, though.
Just wondering if I purchased a copy of photoshop elements 11, is there an upgrade available to the regular photoshop?
Officially NO. You can't upgrade to main Photoshop CS6 software unless you have already bought the previous versions of Photoshop (CS4, CS5, CS5.5). Not sure what made you ask this question. If you want to buy Photoshop CS6 then you could try Educational version but this only applies if you are in some form of education at a recognized School, College or University or you have children attending the education system.
Also, if you are going to do lots of work in Photoshop then it is a good idea to buy the full product now so that future versions can be upgraded on a regular basis.
Hope this helps.