welcome to WebmasterWorld [webmasterworld.com], tbrim20!

i think this would work:
- you create a script that runs under the old domain and internally rewrite all appropriate requests to this script, redirecting all other requests (images, etc) to the new domain.
- the script looks for a cookie and redirects the request to the new domain with an additional parameter containing the cookie data; if no cookie exists the request is redirected to the new domain otherwise unmolested.
- on the new domain, requests containing the cookie parameter are internally rewritten to another script, which constructs a 301 response redirecting to the "cookieless" url and including the cookie.

to review, this should work thusly for search engines, new visitors and other requests with no cookies:
- "cookieless" request to old domain gets internally rewritten to script
- script 301 redirects request to new domain
(note: you could even use a RewriteCond to test for the cookie and skip the rewrite to script, just redirect to new domain)
- new domain provides a response with a new cookie

and for returning visitors that permit and have a cookie:
- request to old domain gets internally rewritten to script
- script 301 redirects request to new domain with additional cookie parameter
- request to new domain gets internally rewritten to script
- script provides a 301 response with a new cookie and no cookie parameter in the url.
- 2nd request to new domain now includes a cookie

Thanks phranque for answer. I've been trying to make sense of how to implement it but unfortunately haven't come up with my own solution.

I'm new to htaccess and still learning so bear with me. But I've been giving this more thought and I think I've come up with a simpler way to do what I want.

But I would like a little bit of input on how to get this to work (if it is possible). But here is what I was thinking...

1. user visits Old_Domain
2. htaccess checks for "revisit" cookie
3. if cookie is set then redirect to specific page for return visitors on New_Domain
4. if cookie is not set then redirect using 301 to same page on New_Domain

So here are the questions...

1. Can I do this type of cookie based redirect along with the 301 redirect and still transfer all SEO from the Old_Domain?

2. If it's possible, how do I set up the order of operations to check for the cookie first and redirect accordingly?

I would want to use both of the follow (note: _ is only used so it doesn't create a link)...

Options +FollowSymLinks
RewriteEngine on
RewriteRule (.*) _http://www.newdomain.com/$1 [R=301,L]

RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_COOKIE} ^.*cookie-name.*$ [NC]
RewriteRule .* _http://www.newdomain.com/page.html [NC,L]

I'm sure I'll have more questions but thanks for the patience and helping a newbie willing to learn.