Not really. Just use the + button to zoom into the part of the picture you want to check the focus of.
I'd honestly go with the 3100 and save money for lenses and stuff. I have a 3100 and a friend has the 5100, and the difference isn't really enough to justify the extra money. The 5100 sensor is nice, but not $250 nicer. You really won't notice a difference. Unless you really feel like you need a rotating screen, just stick with the 3100. If I was gonna buy something in Nikon's current line up over the 3100 it would have to be at least the D7000. The 7000 has the same sensor as the 5100 but has a better AF system, better build construction etc, which are things that really matter. The 2 megapixels between the 3100 and 5100 don't mean shit, so don't base your decision off of that.
"there's a certain point where it neither looks good nor functions properly...that's when you know you look steezy" -no_steeze