You can add iframes inside the pageviews in order to load pages, not user controls.
Regarding your first question, you can access the tabstrip from the user controls like this:
RadTabStrip tabstrip = (RadTabStrip) Page.FindControl(
and then find its SelectedTab.
Hope this helps.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items.