.htaccess Help Needed

I need your help on this

[fabian]

Hello. I need some help to write a .htaccess .
My site is hosted into a linux apache server.
I need to block access to users coming from a determined host.Example , I need to block access from [widgets.com...]
Could anyone give me a suggestion on what to put
into my .htaccess file?. Thanks in advance

[ScottM]

I believe there is a very good tutorial found here:
[httpd.apache.org...]