Well, the title said it all. Here are some screenshots about the labs in Packet Tracer Simulator:
CCNA Drag And Drop SIM:

CCNA EIGRP SIM:
Configuration SIM:

Please say thanks to Runiya, who created these lab-sim questions on Packet Tracer. Now you can practice with real labs in your CCNA exam!
The lab file includes:
+ CCNA Implementation sim
+ CCNA drag and drop sim
+ CCNA EIGRP sim
+ CCNA NAT sim
+ CCNA RIP Configuration sim
Link to download these labs
Download lab files from 9tut
Fred contributed the new access-list sim for us, please say thanks to him, too!
Download Access-list sim lab file from 9tut
Download the VTP sim shared by Zeldall:
http://www.valit.ca/lab/ccna/ccna_vtp_sim.zip
You will need Packet Tracer to open these files. It's totally free! You can download this software but you need to register first or you can find a mirror download with google (with keyword "download packet tracer")
Please notice that in real exam, you have to click on host (PC) to access command-line-interface of the router, not the router itself.