It's tricky to get the link to the DispForm.aspx of an SpListItem from the SharePoint 2007 object model.
In this sample you can find a piece of code to get the exact list item's url:
using (SPSite site = new SPSite("http://yoursite"))
{
using (SPWeb web = site.OpenWeb())
{
SPList list = web.Lists[0];
SPListItem item = list.Items[0];
string ItemDispFormUrl = String.Concat(item.Web.Url, "/",
item.ParentList.Forms[PAGETYPE.PAGE_DISPLAYFORM].Url, "?id=", item.ID.ToString());
}
}
Ops.... I almost forgot: thx peppedotnet.it !