lucy24 - 9:23 pm on Jul 11, 2012 (gmt 0)
You need to find out how the original host's domain redirecting works. From example.com (old) to example.org (new) the two possibilities are:
www.example.com/anyrequestatall >> www.example.org/
(everything redirects to front page of new domain)
www.example.com/anyrequestatall >> www.example.org/anyrequestatall
(file-for-file redirect from old to new domain)
If the old host will only redirect to the front page of the new domain, throwing out the rest of the request, then you'll have to keep the old domain alive for a while.
The minimalist version is to make an htaccess at the old site, containing one line. Well, two:
RewriteRule (.*) http://www.example.org/$1 [R=301,L]
That will grab any incoming request and redirect it, file by file, to the new site. That includes things that you would normally block, or that would be redirected to a different name. Like I said, minimalist version.
The word "blog" suggests that your existing code includes some combination of redirecting and rewriting to make pretty URLs. But that's site-specific, so we would need to know what's currently going on. There will be no rewriting at the old site, but there may be more redirecting, like
www.example.com/longuglyURL >> www.example.org/shortprettyURL
in one step.