One thing you’ll probably notice in our UI is that most of the options for editing the appearance of an item in PGC are grayed out (because we haven’t implemented them yet…).  Luckily, all the visual elements in PGC are Silverlight 1.0 XAML and there are free and fairly easy to use tools available that let you tweak away to your hearts content.  You can also start from scratch if you’d prefer, creating a new XAML file for use in the PGC.  Right now, your best bet for editing the visual appearance of Silverlight XAML is probably the Expression Blend 2.5 March 2008 Preview which is available for free (at least until Expression Blend 2.5 is finished and released) here.  There are other tools available such as Visual C# Express 2008, (heck, XAML is text based XML, so even Notepad will work, although if you’re working with anything aside from simple shapes, a graphical editor is probably useful :)), but at the moment my preference is Blend. 

The basic idea for editing an actors appearance is to go to the appearance dialog, click “Switch to XAML” and then copy/paste the XAML into Blend.  Once in Blend, you can make your tweaks and edits, then paste back the resulting XAML into Popfly.  I’ve put together a quick video tutorial of the process, so check it out: