The following links were helpful whenever I have done Content Type Hub worl.

View error logs for content type publishing

http://office.microsoft.com/en-us/sharepoint-server-help/view-error-logs-for-content-type-publishing-HA101631504.aspx

Republish all hub content types in SharePoint using PowerShell

http://get-spscripts.com/2010/11/republish-all-hub-content-types-in.html

Content Type Hub (Sharing or Syndication) SharePoint Server 2010

http://jimecox.wordpress.com/2010/11/30/content-type-hub-sharing-or-syndication-sharepoint-server-2010/