In this tutorial I will tell you how to make a simple and good boarder!
1st Click at Rectangular Marquee Tool http://img94.imageshack.us/img94/3434/frefr1.png
After mark the boarder of signature http://img36.imageshack.us/img36/1347/tgtr2.png
Then press right click and go to stroke http://img695.imageshack.us/img695/467/trgttrgt3.png
And after put Width 3px, Location> Center, Mode> Normal, Opacity 100% and Color anything you want .. ( black,blue,red etc.. ) http://img294.imageshack.us/img294/5858/bvgrbg.png
And the boarder it's ready! http://img268.imageshack.us/img268/166/gtrgtrg6.png