The code you're looking for is below, I have just implimented this one of my websites - I'm quite new to PHP so there is probably a better way, all I know is it works on my site using CB 1.0-RC2 with Joomla 1.0.8.
You're adding code into the file cb.menu.php found in components/com_comprofiler/plugin/user/plug_cbmenu
Go to line 1146 (just above the "add plugins' status" section) and past the following code
[code:1]// Profile Link
if ($params->get('profilelink', '1')==1) {
$mi = array(); $mi["_UE_MENU_STATUS"]["Profile Link"]["Profile Link"]=null;
$this->menuList->addObjectItem($mi, $user->username, sefRelToAbs($user->username), "",
"","", _UE_USERNAME,""«»);
}[/code:1]
You can change the title of the 'menu item' (in this code it is "Profile Link") simply by changing both
[code:1]$mi["_UE_MENU_STATUS"]["Profile Link"]["Profile Link"]=null;[/code:1]
to
[code:1]$mi["_UE_MENU_STATUS"]["Homepage"]["Homepage"]=null;[/code:1]
or what ever you wish to change it to.
This will display the username in it's own section linked to
www.yourdomain.com/username
I haven't quite worked out how to display the link as
www.yourdomain.com/username but if you want to display it as
www.yourdomain.com/username paste in this code instead
[code:1] // Profile Link
if ($params->get('profilelink', '1')==1) {
$mi = array(); $mi["_UE_MENU_STATUS"]["Profile Link"]["Profile Link"]=null;
$this->menuList->addObjectItem($mi, sefRelToAbs($user->username), sefRelToAbs($user->username), "",
"","", _UE_USERNAME,""«»);
}[/code:1]
Same rules apply with changing the title.
Enjoy,
Ryan