changing url and permalinks

Hi.
I was playing with my first WP blog, while it was a subdomain/add-on of one of my other sites.

So now that I’ve got the layout mostly ok, I was planning to get the permalinks and everything setup correctly. I’m a search engine nut, so wanted to make it as SE friendly as possible.

I’ve deleted all the old posts, started it up again with 3 pages and 1 post, and bought a domain name. (My first .com.au one). It will still be physically hosted in the same place as a subdomain of my main site.

So do I just go in to Options>General, and change the WordPress url AND Blogaddress url from http://best-australian.com/geekmum to http://www.geekmum.com.au ? Or is that going to stuff things up severely?

My htaccess file also looks reeaally messy, as I was experimenting with the permalink structure during setup. It looks like it has two structures defined – the original one, and then the current /archives/%postid%.

If I want to change it to /%year%/%monthnum%/%day%/%postname%/ , should I just delete the contents of the current htaccess file, chmod it, then go to WP>Options>Permalinks, change the structure, let the permalinks regenerate, and chmod it back again?

I wanted the htaccess file to be neat so I could easily add some specific redirects later on.

What are the odds of it working? Any tips?