I'm looking for a laptop that can easily substitute for a desktop has great gaming capabilities (Good enough to run Sims 3 or Sims 2) all for under $600.00

I'm afraid you'll be pushing it to get a laptop under $600 with "great" gaming capabilities. However the Sims is not a graphically intense game so you should be able to get a laptop that can run the Sims with little trouble for that price. You are going to want a laptop with a true video card, not integrated graphics. (The graphics processor has its own memory, integrated graphics share memoery with the system and this reduces performance.) Your best bet is the MSI CX600-049US. 
A run-down on the specs on this computer:
    * Intel T4200 2.0GHz Dual-Core Processor
    * 4GB RAM
    * Hard Drive Capacity 320GB, Optical Drive Included Supermulti DVD-RW
    * Windows Vista Premium, Eligible for Window 7 upgrade Program
    * LCS Screen Type WXGA (16:9), Video Graphics ATI HD 4330 512MB; VRAM Graphic memory 512MB DDR2

For gaming the dual-core processor and ATI Radeon HD 4330 with 512MB of RAM are the important features you will want here. The 4GB of system RAM and large 16" display also make this a great desktop replacement notebook. You can buy this computer for $599 with free shipping from Amazon. Thank you for using IMshopping.