I have a client site built with Classic ASP techonolgy. I'm trying to determine what my options are for a blog for his site. The host does not offer anything. The client definitely wants the blog to be integrated into the site.

OPTION 1:
Use Wordpress domain mapping, so the site would be blog.clientsite.com even though the "Real" blog would be at clientsite.wordpress.com
PROBLEM WITH THIS OPTION: we would have to use a Wordpress template - so it would not looks the same as the client site - so this isn't an option unfortunately.

OPTION 2:
Get a new host - maybe Wordpress.
PROBLEM WITH THIS OPTION: We would have to migrate the existing site to a new host, and update all the ASP code to PHP - this would take more time, and cost more money for the client, but it is an option

OPTION 3:
Find some kind of blogging software that would could use on his site - like some kind of off-the-shelf classic ASP (or even .net) software that can be installed to www.clientsite.com/blog

OPTION 4: you tell me...?

Does anyone have an ideas? Suggestions, warnings, concerns?

Thanks in advance!

i had to integrate a blog for a friend who's site only allowed html, javascript, and css.
i used tumblr, its easy to integrate and totally customizable. it can be customised to match ur clients site. just search it on google how to style it.