Yes, a frame would be terrific and also a silk scarf gracefully cascading over the top would be a 30 second solution and help soften the square edges.

Swag it top and sides with fabric falling

Framing it in would look awesome. Maybe butt the two mirrors up to each other and then frame it. Here's a great step by step tutorial. http://www.sweetpickinsfurniture.com/2010/05...

You could use cheap 5 x 7 or 8 x 10 frames without the glass and adhere them to the mirror side by side. It'd end up looking like a french door mirror. :)

Home Depot has squares of this decorative sheet metal. You could cut them into strips and use them around the mirror, then attach painted half-circle dowels to the edges for a modern look.

http://bit.ly/Mjsi4D

What is your decorating style for the area adjacent to your mirror?

I love that clock you have hanging in the back!

To play off of the really cool clock you have, I would find some scrolled plastic in a cool pattern, paint it black and wrap it around the bottom and part way up the sides overlapping the mirror just a bit in a couple of places. If you cannot find scrolled plastic, use heavy wire and twist it into the desired shape, paint and then wrap the mirror in the above pattern I suggested. Just my idea of what I would do.