i made my page so that its perfect in 1024x768 resolution, but now it looks really small in higher resolutions. What do I do?
I'd let the user worry about it because all modern browsers (at least the ones I've seen, even IE) allow you to zoom in page contents (Ctrl-mousewheel on PC, not sure about Macs).
Also, and this is just an assumption, If someone is stuck with IE6 or IE7, they might night have a monitor much bigger than 1024x768.
People with very large resolution monitors rarely run their browsers at full screen, so 1024 is still a good width. If they are running at or near full screen on a big monitor, making a flexible page widths can be a problem - especially if you have text columns that might get too wide to comfortably read (it gets hard for the eye to follow too-long lines).
So, although it is true that monitors have gotten bigger and bigger -- http://www.w3schools.com/browsers/browsers_display.asp -- you don't have to worry about using up their whole screen. And, there is a fast-growing number of netbooks and ultra-lights with small screens, so 1024 x 768 is really quite reasonable.
You either 1) do nothing: This is the web, and resolution tells you nothing about how a user is actually viewing. For example, each of my monitors is 1280px, but I use sidebars to narrow the viewport to around 900px, as that gives good line lengths on many sites I frequent.
2) If it is a fixed-width layout, you might consider centering the layout when it is in a wider viewport. Do NOT use negative margin techniques for this (I've seen a couple of sites where users with narrower windows lose some content off left and can't scroll to it).
3) Make you layout fluid (see Tony's suggestion). You would normally give fluidity to the main content column, but set a max-width in ems to avoid excessively long lines of text (hard to read) and a min-width so that the fluid column doesn't become unusably small in narrow viewports.