Ye' can change yer password by clicking the 'Forgot your Password?' option at the very top of the page. Ye' can also change it by goin' to yer profile, scroll down until ye' see 'Modify Profile' at the left side of the page, look under it to see 'Account Related Settings'. Click it and within' it, ye'll see the option to choose yer own password. However, to change yer password, ye' must accept its change in the e-mail ye've set up yer account in. When it's changed, it does change for both the forum and in-game.
By the way, I like yer avatar. -Obvious OFF fan.-