changing the “home” variable

I would like to change the “home” variable that is used to construct paths across much of WP. Could anyone advise me how to go about this? I managed to change the “siteurl” value by updating this field in the DB (wp_options table), but so far I haven’t had as much luck figuring out what to do with “home”.

The reason why I’d like to do this: My blog exists as a subdirectory of my larger website, and as you would expect, the path to that subdirectory is the value contained within “home”. But I purchased a domain name for my blog and have set up my DNS to forward to the subdirectory with cloaking. I would like my blog to appear like it is an independent website rather than revealing that it exists as a subdirectory. The only thing preventing this is the path that shows up on the statusbar when you hover over certain links that use the “home” variable. I could write javascript code for each of these links to display something else in the taskbar, but the cleanest solution would be to update “home” and take care of it in one place.

By the way, I’m also confused what the difference is between the “siteurl” and the “home” variables. Are they defining the same thing, and if so, couldn’t they be combined into one?

Thanks in advance for your help.