aloha dndstef,

I'm gonna answer, and hope will help u....But, before that... what version of SQL Server are you using now ???
My answer below will be around SQL Server ver. 7.0

1- Do I need Win NT server & SQL server to create a SQL DB?
To create SQL DB, of course you need SQL Server... If you don't have any SQL Server, how can you have a SQL Database. But.... There are several kinda SQL Server.... They are SQL Server itself, MySQL, ....etc....

I'm gonna talk about SQL Server ver 7.0
SQL Server ver. 7.0 can be installed on a single station, on Win 95 / 98 Platform, or on Win NT 4.0 Server / Win NT 4.0 Station / Win 2000 (Server nd Station)

But, my suggestion, for Server installation, you can use Enterprise Edition / Standard Edition.
But, for Single Station installation, you should use Desktop Edition.

Is it Help ???

2- Is it like a access DB?
For SQL Server ver. 7.0... yes... almost like Access DB...
But, there are some differences in SQL Server ver. 7.0

Some new features I know (the difference between SQL Server ver. 7.0 and Access DB) :
*. SQL Server 7.0 has Stored Procedure, the place where you can put your Procedure on Server, so your VB / your application program (which use SQL Server) will run faster, coz the Procedure will run at your Server.
*. In SQL Server 7.0 you can admin your user, and their access to your database.
*. You can connect from SQL Server to SQL Server, and make a replication data from one server to another.
*. SQL Server 7.0 serve you with a SQL Query Analyzer.
*. SQL Server 7.0 stores more records size than Access DB.
*. To connect to SQL Server 7.0 you should use ADO connection while to connect to Access DB, you can use DAO connection.
*. etc.......

3- When should I use a SQL DB rater than an access DB?
I think it's up to u man... But, when your Access DB can't hold your data records, I think you should change to SQL for better records holder.
But, when SQL can't hold your data records, you still can change to Oracle Database.

4- Is there any documentation on the net to learn SQL DB, some tutotrial or so?
Yeah, you can learn SQL Server....
try to find the SQL Server website at Altavista Web Search Engine.

ok ???
Hope will help you...

Cheers,
Wen Lie