As soon as you pop in you sim card the iccid will show up.
I bought one off ebay too and was wondering why I had no iccid.
I don't know if using yessim or stealthsim is good because sometimes that messes up the iphone. Right now I'm using at&t for my 3g so I theres no need to unlock it. On my original Iphone that was running 2.0 I had to downgrade that back to 1.14 (I'm not %100 sure if you can do it on the 3g but im pretty sure you can because its the same firmware) to downgrade I had to get itunes 7.5 and download 1.14 after I do that I put my phone in DFU mode then I hold shift and click restore and click my 1.14 firmware. Then on the installer app in your iphone download BootNeuter having them at these settings: 3.9 bootloader ,neuter On, fakeblank Off, unlock on. Go back to itunes 7.7 your going to need a custom 2.0.1 custom firmware (
http://appldnld.apple.com.edgesuite....8_Restore.ipsw) get ilibery and put into normal recovery mode hold shift and click on restore and find that custom firmware. hopes this helps lol