Maximum length or URI in GET method

[toolkit]

Hi there,
I have a requirement to provide the capability for a user to mail a URL to another user in order to generate a report. At present, our reporting system uses a POST method, as the number of parameters used in generating a report can be quite large. I am considering what limitations may be experienced if I switch to a GET method, so that the URL on its own will contain all the information required. Is there any hard-coded limitation you know of with Apache with regards to the maximum length of the URI in an HTTP request?

Thanks for any information, cheers Neil