From Wikipedia

A palindrome is a word, phrase, number or other sequence of units that has the property of reading the same in either direction (the adjustment of punctuation and spaces between words is generally permitted).

I thought this video was pretty neat by Al Yankovic

[youtube:http://www.youtube.com/watch?v=PsgeTNnYywg 300 400]

Here is Bob Dylan's Original

[youtube:http://www.youtube.com/watch?v=2-xIulyVsG8 300 400]