okay, a quick question... should I use a php include to include meta tags? what about a php include to include the same meta tags on every page? sorry and thanks
Meta tags should be individualized for the page, not uniform throughout a site. The title tag and the description tag are important. The keywords tag doesn't matter much any more but won't hurt - even there, make it appropriate for an individual page, not the same for the whole site. Given that, I'm not sure it makes any sense to do it via php includes in most cases - you'd need a different include for every page anyway.
Yes if you make your tags uniform you will not receive as many hits on pages that would do better if they were setup for the keywords of that page.
I use php includes for site design but leave the meta tags on the content pages. When I add content pages I also add the meta tags at that point.
The benifit of using the include is ease of management. We use a single file to include meta tags into each page on the site - obviously each page has it's own unique title, desc and keywords.