How long is cream cheese icing good for? i made some last sunday and i have a cake due this saturday, i was thinking of using it as a filling if it would still be good. it's been sealed up in my fridge. thanks

Well, as long as the cream cheese best before date is well within this time frame and when you whip it up, it looks good, it should be just fine. Icing made with butter, cream or milk and/or cream cheese, should hold up for up to 2 weeks (always check the best before dates on the dairy products and insure they are within the time frame) although, I prefer to stick within the 1 week to 10 days timeframe.
If you coloured your icing, it may get a funny smell from the food colouring. If this is a pretty standard cream cheese icing made with mostly cream cheese and icing sugar and butter, it will be fine. The only time you will have an issue is with an icing where one of the main ingredients is whipping cream.
Hugs Squirrelly Cakes

..for future reference...when you have left over cream cheese icing, pop it in the freezer to store it!!

thanks for the freezing tip. i had a ton left over and didnt know what to do with it. next time i'll be able to save it .do you know how long it lasts in the freezer? also, can i freeze regular buttercream then? thanks

I don't know if there is a rule of thumb but I've frozen cream cheese icing for up to a month and it was fine. Buttercream freezes just perfect for several months...just bring to room temp and give it a good stir and you are good to go!