I'm such a newbie in WP

, thanks a lot !
[LE]
Well I just did something bad, I've set the default page in a wrong session, instead of setting this in the Reading submenu I did this in the General Setting area, changed the wordpress (I know is stupid) ... but I can't access the wp-admin page anymore to go there to fix this ... any idea how can I fix this ?
Any idea where the WordPress address (URL) and Site address (URL) in General Settings are stored, maybe I can change them manually somewhere ?
[LE2] Ok I've fixed this, accessed the Mysql database and changed the "siteurl" field