If ya go into your admin/options/general...you know...the sorta of admin control panel in your WP.
then chnge the URL to the one you would like it to be in...or back space the /blog/wordpress off the end.
Do the same to the one below.
then go to the directory that you wana place WP in and make sure there is nothing that will be overwritten.
Then when your ready....move all the files to the directory you want them in.
Did that make sence to ya? :)
also...ya might want to inform people that have linked to pages with in your WP about the move ;)