i phone error 9808

After a quick Google search there appear to be two fixes.

1. On Microsoft Windows XP, not sure if it's the same on Vista (post in comment if you have any idea, thanks!). In Internet Explorer, go up to Tools > Internet Options. Then go to the last tab, Advanced, and scroll down to the Security section. It is the fifth box down and make sure "Check for server certificate revocation (requires restart)" is unchecked. Then access the iTunes Store as usual and hopefully it will fix the iTunes 9808 error. Best of Luck!

2. The other was DNS related so I would go with option 1.

Make sure you have USB 2.0 and follow my steps too as below........I had mega problems. Try following the steps in my posting as below after creating a new user account on your computer with ADMIN priviledges also. See my posting on 20/06/2009 22:33 titled "Upgrade Error number 4 and Restore Error 1603 when going to OS 3.0 - Solved"

And turn off any antivirus and firewall software too, before doing so. In ITunes, highlight your iphone icon and then click the Restore Button on the ITunes Summary tab which seems to force the iphone into an update. Dont try using the Check for update button. Good Luck...........

if it doesn't helps (like it was by me) you should search for certificates in the content tab/certificates.
Then delete 2 certificates which end date is close to the date you began to have problems.
Restart the connection
iTunes downloads new certificates and it works
Regards