Do 看一看 and 瞧一瞧 have the same meaning? Is 看一看 equal to 瞧一瞧 in meaning? 

Are they interchangeable?
In Northern China, 瞧 is the colloquial form of 看 and they are always interchangeable. I can't speak for Southern China though.

E.g.


瞧瞧 = 看看 = take a look
你瞧瞧 = 你看看 = [in blaming tone] look (what you've done)
瞧一瞧 = 看一看 = take a look (don't miss it)
瞧得起 = 看得起 = look up to
瞧得见 = 看得见 = can see
瞧一眼 = 看一眼 = cast a glance at