That question is a bit vague because there are several languages that you can use to create a website and also lots of programas that help ya using them! There's programs that only check one programming language syntax and others that check various languages!
I use Ace HTML editor 4.0 wich is not free but ya can use it for a 30 day trial.
Crimson editor, i used this program during my trainee in a webdomains company seller, this program is free but not very user-friendly!
Macromedia Dreamweaver is the most user-friendly program that i know for that kinda purpose! I can also crac...

Macromedia Flash for animated websites!
It's a matter of searching, i'm sure that there's lots of them over the web!
Once again, the Open-Source software (Sticky) topic comes to mind, make an effort and ask Saint to make it sticky!
