I reckon Data Transformation Services in SQL Server 2000 are a good thing, and have used them to import and process text files into my databases. With a bit of mucking around you can do almost anything with DTS, like checking for file existence and setting the target database, among other things. You can even execute a DTS package from a stored procedure, which is perfect for calling from a custom user interface, setting global variables and doing extra processing.
A rough example:DECLARE @rc INT, --return value from "exec" calls
@pkg INT --pointer to package ('object token')