Hi,
I you are preparing for the lab, then what you want to do is get yourself a workbook from one of the main vendors, it would be a good idea to get one from 2 different vendors to get another approach.
The main vendors are, in no particular order;
ipexpert
internetworkexpert
netmasterclass
netmetric solutions
metronics
ccbootcamp
When you get a workbook, you can either use dynamips on a good pc, or if you have your own rack with some of the newest hardware, or even use an online rack provider, such as cconlinelabs and racktimerentals
All workbooks will use a specific physical topology so when you cable your rack for one workbook you will be able to do all labs, normally, from that workbook provider.
HTH
LR