What are the chances of it sending one day? (it has been three weeks all ready) is there an easy way to remove this?
You can remove it using the pywallet tools (be very careful and make sure you back up your wallet before playing with it).
The other thing you can do (if you still want to try and send it) is to right click on the tx and copy the transaction id then from the "console" (you can get to from the help menu) you get type: getrawtransaction <pasted txid> (be sure to remove the trailing -000 which is annoyingly always put there when you copy a transaction id to the clipboard).
You can then go to
http://blockchain.info/pushtx and paste the raw transaction hex into it (no guarantee it will work of course).