hope this helps you out some. we have this rule in out site.

RewriteRule ^go/(.*) aff.php?id=$1

domain.com/go/4
goes to
domain.com/aff.php?id=4

i know its not exactly what you need but hopefully it is close enough you can change it to work for you.

not sure if im right but it would look like this if i am.

RewriteRule ^index.php/(.*).html index.php?id=$1

give it a try and let me know

are you using wordpress?

Something similar can be accomplished using the

AcceptPath Directive

if your host supports it (most do) if not, mod_rewrite is the way to go