Question: How would I extract Active Directory info (Username, first name, surname) and populate an SQL table with the results?

Many thanks

Scott

Answer: 
The way we do this for a **LARGE** AD environment:

1. Nightly batch process that runs [AdFind](http://www.joeware.net/freetools/tools/adfind/) (freeware tool) to execute an LDAP query and dump it out to CSV files
2. [BCP](http://msdn.microsoft.com/en-us/library/ms162802(v=SQL.90).aspx) (built-in SQL command line tool) to bulk import the CSV files into import tables in the SQL database
3. Stored procedure (executed with [osql](http://msdn.microsoft.com/en-us/library/aa214012(v=sql.80).aspx)) to take the data from the import table and add/update records in the main tables

We pull 145k users, 80k groups, 130k computers from 10 domains in about 2 hours from start to finish. This includes pulling accurate LastLogon information for the users and computers which requires you to hit each domain controller. Without that, the process takes about 30 minutes.
If you're on .NET 3.5, I would use the new `System.DirectoryServices.AccountManagement` namespace for this.

Learn about it here:

[Managing Directory Security Principals in the .NET Framework 3.5](http://msdn.microsoft.com/en-us/magazine/cc135979.aspx)

Basically, you'd set up a container (a `PrincipalContext`) and then enumerate the users you want to deal with. Loop over those and extract the info you need, and feed that into SQL Server.