You can create your application use LINQ to SQL and make it N-Tier. Go ahead and watch out the MSDN Documents
N-Tier and Remote Applications with LINQ to SQL
LINQ to SQL N-Tier with ASP.NET
LINQ to SQL N-Tier with Web Services
LINQ to SQL with Tightly-Coupled Client-Server Applications
Implementing Business Logic (LINQ to SQL)
Data Retrieval and CUD Operations in N-Tier Applications (LINQ to SQL)
Namoskar!!!