This article (which pretty much constantly seems to be down for me at the moment) presents an interesting was to nest Repeaters etc... in ASP.NET, now I have never used this approach - and I have no idea what method is best (and I suck at writing so, I'll probably update this a LOT). What I generally do is use the OnItemDataBound event to bind child tables on to the nested repeater to do this you simple create an ASPX page with a repeater into which you nest a second repeater.
In the first repeater, you use the OnItemDataBound event (ItemDataBound from the code-behind) to pull out a DataTable using a DataRelation and bind it on to the 'child' repeater...see the project for a complete implementation using Northwind.
I've made the complete project avaialble here.
UPDATE: Sorry, I've had to pull the source for now, having major problems with the .TEXT editor...hmm...anyway, feel free to download the project and have a dig around, happy to answer any queries!