This is a very easy and good recipe to pour over your fish.
1/2 cup dry white wine (chardonnay, doesn't need to be $$$)
1/2 tbsp finely chopped shallots
1/2 lemon - optional
1/2 stick butter
boil up the wine and shallots (and lemon) in a sauce pan (not frying) and reduce it down so there is about 1/4" liquid at the bottom - about 10-15 minutes. Take it off the heat and start adding the butter in small pieces - stirring as it melts. If you leave it on the heat, it will separate the butter and you need to start over. You can use a very low heat.
Then pour over fish.
If you want it thicker, add a little 1/2&1/2 cream - thicken to your liking.
Or you can follow this:
http://culinaryarts.about.com/od/but...eurreblanc.htm
I've done this a number of times and it is really easy. I've used the wine at Fresh&Easy - $1.99 - works fine for cooking.
This is good for two servings.