Damian has the best news possible for everyone:
After further investigation, it’s been determined that SP3 is OK as is and the initial files will be reposted this evening without any changes. Anyone who may have already downloaded SP3 should use what they have downloaded already as we have not changed the setups and what you may have downloaded is good.
The issue that caused the confusion is related to the use of Boolean values in GP tools in .NET. At 9.2 there is a bug that the TRUE value never worked for these GP tools, and the FALSE value only worked in some limited cases. Given that, we feel that the changes in SP3 have a positive impact on a majority of the user community and limited negative impact on very few applications.
There is now a Knowledge base article describing the API change as some people will be affected ( http://support.esri.com/index.cfm?fa=knowledgebase.techArticles.articleShow&d=33441 ).
I will post an update as the files go live again on the site.
Again I apolgize for the confusion this caused.
The files are back and those who have already downloaded the SP3 won’t have to download a new version. Thanks to Damian to getting the word out on this. If you are still confused about what happened and why people were getting errors, make sure you check out the KB Article on the changes to ESRI.ArcGIS.Geoprocessor at 9.2 SP 3.