Simply put, People don't say a photo has been edited any more, They say it has been photoshopped, I've been using photoshop since version 7 and I have to say CS2 is my favourite version by far, Not too keen on the new-ish CS3 as it seems more gimmicky and the GUI has been messed around with which is a bit annoying considering they cracked it with CS2.
It really depends what you want to do as far as buying this package goes, If all you want is to fix some images, Remove red eye, Crop, Fix color balance etc. then you would only really need Photoshop Elements or Adobe Lightroom, But if you want to be able to go anywhere your creativity takes you then This full version is essential, As for learning photoshop just search "Photoshop Tutorials" and do a few of the millions of tutorials online.