[quote]location ^~ /weblog/ {
rewrite ^/weblog/(.*) /blog/$1 permanent;
}

I believe there's also a way to use regex captures in the location.
I've not used this method yet, but I believe it's something like this:

location ~ ^/weblog/(.*) {
rewrite ^ /blog/$1 permanent;
}[/quote]

Both solutions appear to work perfectly!
Thanks so much, Nick!