All of the information regarding Site Selection for the 2008 USA Olympic Marathon Trials is being released officially this week by the USATF National Office.
The standards will be released with those documents. Also the process and timetable for site selection will be announced.
No big surprises. Standards, at this stage, will be very similar to 2004. There are two sets of standards - the IAAF standards for qualifying for the Olympic Games (these standards 'A' and 'B' have been subject to change in the past by IAAF. Then there are the USATF qualifying standards for the Trials - again 'A' and 'B' standards - similar to the last time.
So be patient a little bit longer and you will have all the information you need regarding standards, qualifying window, and process.