I wonder if someone knows if there is a pre-made solution for this: I have a List on an ASP.net Website, and I want that the User is able to re-sort the list through Drag an
This is just personal opinion, but the problem I find with ready-made controls in cases like this is that they are extremely bloated, because they're trying to fit everybody's purpose. If all you need is a sortable list then a simple Scriptaculous list or jQuery list with a quick WebMethod callback should fit the bill quite nicely, and you can obviously stick this into your own user control.
As I say, just my opinion, but I wouldn't go spending money on something that's going to add tons of overhead to my page, when I could spend (literally) 10 minutes writing one for free.