How do you take songs off your ipod [Touch]?

Well, i was stoked when i got my ipod touch, went to my uncles computer and put a bunch of songs im not really even crazy about. Now im starting to download all the good stuff but i dont want the crap thats still on there. Can you give me a step by step walkthrough on what ons to push and where to go on iTunes (8.0), to take off certain songs that i dont want. Thanks to all the answerers and the help.