The Icelandic Road Administration publishes information (a map) on the condition of mountain tracks in Iceland during summer. Here you can click for a GIF image of this information or a PDF document with this information.

The Icelandic Road Administration has an english section on their website with links to useful information on driving in Iceland.
The Traffice Directorate also has an english section on their website with useful information for tourists driving in Iceland.

On www.visiticeland.com you can get lots and lots of information on travelling in Iceland, and in various languages.