Ringtones can be downloaded through cydia, or created for free with a program like Garage Band. You have to download themes/tweaks through cydia and then you can apply them in WinterBoard by checking them, and moving them higher on the list (that indicates priority), once you exit out of WinterBoard the phone will respring and the themes will be applied.
...and then apply the theme with Winterboard (what you'd need to use if you downloaded the theme from Cydia also).
Are you talking about Matte UI?
i have no idea how do anything ? how do i go about changing ringtones .. etc .. themes ? i downloaded winterboard but i dont see any options to load themes ??
any recommended programs ?
Right, Matte UI however is not on Cydia (at least not a working version).
You can find Matte UI here: http://macthemes2.net/forum/viewtopic.php?id=16792850&p=73
Not sure if there's a later release after that; I haven't checked the thread. But i'm running the aqua one in post #1820 with a modified dialer pad and it looks great.