How can I fade in text-decoration css with jquery?

[delean]

I have the following code:\[code\]This is a <span id="sentence">sentence</span>.\[/code\]When a user hovers over \[code\]sentence\[/code\], I would like an underline to fade in under the word.This seems like such a simple problem, but I have not been able to figure out how best to do it. Just to be clear, I cannot just use \[code\]css:hover\[/code\]. I need to do this with JQuery given the actual problem is more complicated and requires more control than that illustrated here. Thanks very much for your help in advance.