Many people ask me the location of ipcc file. I really didn't know why they ask this...because I thought only a little effort should you need to put in to find in your PC - that is what I found wrong. At some point in 3.0 Beta release (possibly, from Beta 5), Apple abandoned ipcc file (or concealing the file) and now that you have an official release of iPhone OS 3.0, you cannot access or find the file anymore.
Luckly, we have a way to handle this situation. If you use AT&T, you can download the file from:
http://www.joachimbean.com/iphonefiles/ATT_US.ipccIf you are in Japan and using Softbank carrier, I have the file. Please let me know if you REALLY want this file.
One more thing you need to be aware of. The current iTunes 8.2.0.23 does not have a function to replace your ipcc file in your iPhone. So, you need iTunes 8.2.0.10 which was provided with iPhone OS 3.0 Beta 4. You can download this version of iTunes from say,
http://www.megaupload.com/?d=DGZHXTHEUninstall the latest iTunes and reinstall this 8.2.0.10. You can replace your own ipcc file by "Shift"+clicking on "Check for updates" button. Then select ipcc file type in pull down menu to choose your ipcc file.
Someone says that simply emailing .ipcc file and opening it with iPhone can insalll your ipcc file onto your iPhone. I haven't tried it but this would be more easier than using older iTunes.
GOOD LUCK!