I'm just curious if anyone has any knowledge of what types of links spiders follow. On one of my pages, I realized I was using a form simply to navigate to another page on the website. I'm guessing that spiders don't follow form buttons so I have since changed them to regular text links just to be safe. Does anyone have any idea on that one?

Second, do spiders follow links that have variables in them for example, 'index.php?all=true'? I'm just curious because I fear that much of my site isn't getting indexed because of this. Does this simply vary between search engines?  Thanks so much.

In so far as I am aware from my own experience with google, dynamic URLs will only be followed if the links are on 'ordinary' non-dynamic pages.

As long as you have a sitemap HTML page then you should get everything indexed.