The washer pump on my corsa also went recently. The guy from the spare shop said it's a common fault with these pumps as when they get filled with dirt they tend to go.
The washer pump is located below the washer fluid water tank. You will have to remove the container/tank disconnect the electrics connection and water connection and the pump should come out.
Replacement pumps are available at extortionate prices from your local vauxhaul dealer, but try Ebay or a simple search on Google to get a bargain.
Make sure you get the right model though!
Hope tht helps.
Bhimski
February 2009