Redirect links in subdomain install to root install.

I want to move my WordPress install from the sub-directory to the main directly but the install has been running on the sub directly for a number of years how do I redirect all the links properly?

Let me be clear I know how to move the actual WordPress install via the Moving WordPress page on the codex.

But what about all the external hardcoded links after 5 years of bloging, posting to the sub domain? I know I might need to do some htaccess magic… I know how to make a simple redirect in my htaccess file but not sure how to redirect every link in a sub domain.

Example of what I want to do:

http://robertdall.com/blog/2008/03/25/the-history-of-podcasting/

would redirect to

http://robertdall.com/2008/03/25/the-history-of-podcasting/