A brief guide to what to look out for on a good Christian website:-
1. Check to see if the site has a "statement of faith", or "articles of faith" (and read it!). This is a good way to determine whether or not the site is rooted in mainstream Christianity or is a cult based faith.
2. Does the site have a contact page? Without a contact page you have no way of contacting the author or webmaster should you have any questions about the content on the site.
3. Christian articles on websites about matters of faith should always refer or allude to the scriptures. The origins of Christianity are recorded in the bible, and hence the bible is the main reference point for any discussion about doctrine or Christian belief.
4. Another sign of a trustworthy site is whether or it's content is linked to or from other established Christian sites, and whether or not the site links out to other authoritative sites on the Christian faith, for example, Bible Gateway (www.biblegateway.com) or the Christian Classics Ethereal Library (www.ccel.org).