How to Delete a Twitter List
Even though this is very simple to do, it's not always obvious! Here is the very easy method for removing a Twitter list that you don't want any longer.
1This will open up the list for you.
2You will see a message that says "You created this list". Underneath it, you have two options: "Edit", and "Delete".
3The site will ask you if you really want to do this as there is no undo. Click OK, and your list will be deleted. You will be taken back to your Twitter stream.
4If it hasn't, either try again or wait for it to update.