AD and Sharpoint Sync

Hi,

I have a situation where I need to programmatically sync Ad users with Sharepoint.

Our environment has trust issues and uses ADFS as authentication provider. So I am looking for an alternative to people picker to add users. Righ now AD user gets created each time has to recreate a contact in SharePoint manually. But there are a hundreds of contacts that we need to sync.

So how can I proceed in this context, I am thinking of writing a code to sync AD users with SharePoint.

Please guide through this..if I can get to see a step by step procedure that would be really helpful.

Thanks