app size...

Hi, A few years back I read somewhere that websites should be designed to work with 800x600 resolution monitors. I, at the time, thought that this was a good idea, and used the same pattern in my software. It made sense to design software so that everyone can use it, including those that have older PCs and smaller monitors. However, as I am far along in my current project, I am running into problems. The biggest of these is that I'm running out of space on the screen to display items. And, if the user is using a larger resolution, when they maximize the program, there is a lot of empty screen (for example my laptop's res is set to 1680x1050. A big difference from 800x600!) Perhaps it would be ok to design it to be optimized at, say, 1024x768? In that case those users with the lower resolution would just see scroll bars. My question is: Is it ok to design software optimized on 1024x768 res and higher? It sure would make a lot of things easier. Thanks for your help.