You could put it in a .htaccess, but it seems to be more graceful to have two vhosts anyway
Vhost1 - your original domain with mod_rewrite settings in either .htaccess or directly within apache
Vhost2 - your target site ie. where you want it all to end up
As for choking spiders.. I can't see why that would happen unless you were doing really complex redirects ie. mapping multiple paths to multiple destinations |