SQL Server Proximity Search Stored Proc

We need a stored procedure created that can take a zip code and distance as an input and return a data set containing records that are within N miles radius of the provided zip code. We are storing data that contains zip codes and latitude/longitude data. The stored procedure will take a zip code input and distance, lookup the latitude/longitude from the database, and then search a table containing numerous latitude/longitude coordinates and return only those within the distance radius from the provided zip code. For example, Execute spGetProximty 94111, 10 will return all points in the table within 10 miles of zip code 94111. Candidates will have strong experience building optimized SQL Server 2000/2005 stored procedures and an understanding of the math involved in doing radius proximity calculations. Samples code and references required. I am aware of sample code that does proximity searching in a stored proc. While this may serve as a basis for this solution, it does not match our requirements and is not optimized. Experienced candidates should have no problem estimating this small job. Successful completion leads to ongoing project work. Thank you.