The difference between them is the Bind method allows ASP.NET 2 supports "the two-way data binding" concept. With this method, we can either fetch data and display them in any data-bound control, and submit changes to the data-store. The Eval method is just a "one-way data binding", meaning that we only can read and display the data, but not writing back.
The Bind method can be used whenever Eval is accepted.
Here there is an example and here you can find info about both methods.
Best of Luck.