hello,

JQuery tutorial below will show you how to make Fade Effect  tabs 

http://www.roseindia.net/ajax/jquery/fadeEffectTabs.shtml

 This tabs(fxSlide: true) function  having two attributes "fxFade" and "fxSpeed" if  "fxFade" set "true" then it show fading of tab content and 

"fxSpeed" is fading effect is set to "slow".