You have explained the process but i need to know which part should i have to insert my jquery. I tried inserting my jquery in the "nice_menus.js" file but nothing happened :( . After wasting hell lot of time in this i found beta4 released in nice menus so i upgraded my nice menu from 6.3 to beta4 . After that some power came to my menu bar, jquerry was working but affected my CSS :( after that i was like totally  --->("0.0"). So i made a quick undo and started to do my own jquery but i got stucked in the insertion. Please enlightnen me . Thanks in Advance

Yes, that's true. Thanks for drawing attention.