I am curently barrowing a friends copy of the GOTY edition, i own the plain one(wanted the expansions to play before skyrim, I bought horse armour and everyother DLC) i noticed on the back the GOTY edition says it supports 1080p while the other says 1080i? is there really a difference or is it still displayed in 1080i even though is says it can go higher on the goty?

From what I understand the 1080i has a little faster resolution.
But it only really matters with a screen larger than 32 inches.

This comes from just talking to a friend of mine though so I'm not at all positive.

im playing on a 58" screen so am I going to tell the difference between the discs?

I don't think you could even tell the difference on larger sets. Even with them side by side. It's still 1080, the only difference is in the way the signal is sent.