Hi,
You will need to bind the relationship to a grid view first. Please look at the http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=3709419&SiteID=1 which has it details and you can refer the following links for more details.
http://forums.asp.net/t/1264723.aspx
http://www.aspdotnetcodes.com/Parent_Child_GridView_DetailsView.aspx
http://www.gridviewguy.com/Articles.aspx
http://www.dotnetreporter.com/postsfromsource.php?feedid=488
Regards,
PAresh