How can I find information that's in my computer quickly. I have a Mac OSX?

Spotlight should be able to do this. Like any search tool the answers you get are only as good as the question you ask there are a couple of sites that may help there are many more sites that also have tips for using Spotlight.
UseingMac.com
(http://www.usingmac.com/2007/11/22/leopard-optimizing-spotlight-search)
Spotlight tips (http://www.macosxtips.co.uk/index_files/spotlight-tips.html)

I agree with cmeeks. Using the spotlight is probably your best option. If you're looking for Apps or frequently used folders, using the Finder is beneficial as well!