To expand on what freegeeks said, you don't really need a lab for CCNA. Dynamips/GNS3 is pretty useful for router stuff, but is very limited on the switch front (yes, there is a 16 port module, but it doesn't have alot of the switch features). My recommendation is to either use Packet Tracker (made by Cisco for the CCNA Academy - you'll need to be resourceful to get it) or build a lab that will be useful for CCNP studies if you plan on going that far.