Resending transaction

I created a send coins transaction when my laptop was offline; now it's stuck at 0/unconfirmed and not visible to the recipient, even though other transactions I created later went through. How do I force the transaction to be re-sent to the network so it can make progress? Or alternately, how do I cancel the transaction so I can get my funds back?

It seems the transaction went through after about an hour and a half.

I'm having the same problem - opened BitCoin to create a transaction and possibly exited before it sent out the payment details. Now I have a 0/unconfirmed transaction.
Having the ability to resend a stuck transaction would be nice - if no nodes have picked it up yet then surely sending it again won't cause an issue (and if some have then they'll just ignore it right?)

Looks like exiting BitCoin should be disabled until each transaction will get at least 1 confirmation 

Phew - it's taken a couple of hours but it's now gone through . Wish I could generate coins more easily! 

0/unconfirmed means that your client has seen the transaction
1/unconfirmed means that your transaction has been included in 1 block, at this point you can be reasonably sure someone has picked up your transaction and it's now in the chain.
as the number of confirmations increases, so does the confidence in the 'truth' of the transaction.
There is no way to cancel a transaction.
It is not possible with the current client to resend a transaction.