I am using ASP.NET MVC3 with jQuery Validate + the unobtrusive validation support that comes with MVC3. Works great for almost everything, but I have one view where there i
I would say what you are looking for is the new support for Remote Validation in Asp MVC3. Here is an article describing a common scenario, hopefully you can extend it yourself. Otherwise there are probably other articles around explaining it even better ;-)
http://www.aaronstannard.com/post/2010/12/07/remote-validation-asp-net-mvc3.aspx
/Victor