The documentation was actually a bit deprecated...I have modified it to reflect the current state of the API.  The test tool is always the best way to learn the actual resources on the REST API.  Note, we will be adding more resources and even have some available that we may not be advertising as we're still finallizing exactly what data we want to make available by user launch.  

 One change you should note...we do not have a specific resource for /topfriends anymore.  Instead, to get top friends you must provides a parameter on the .../friends resource of list=top.  The value may also be online in order to retrieve the friends that are online and soon we will make a available a value of app for the friends using your application.

 Is groups (mentioned in the "updated" REST API doc) supported? It is not in the test tool yet. Thanks!

I just tested it, and it '/groups' works. Here's a sample of the return (as XML):

<user xsi:schemaLocation="https://api.myspace.com/myspace.xsd" [...] />
<userid>123456789</userid>
<uri>http://api.msappspace.com/v1/users/987654321</uri>
<groups count="2">
   <group>
      <groupid>121212121212</groupid>
      <groupuri>http://api.msappspace.com/v1/users/112047910/groups/121212121212</groupuri>
      <groupname>Group 1</groupname>
      <createdate>8/18/2005 9:34:00 AM</createdate>
      <description>Group1 Description: Note - can contain HTML!</description>
      <membercount>55</membercount>
      <memberbulletins>False</memberbulletins>
      <membersCaninvite>False</membersCaninvite>
   </group>
   <group>
      <groupid>2121212121</groupid>
      <groupuri>http://api.msappspace.com/v1/users/112047910/groups/2121212121</groupuri>
      <groupname>Group 2</groupname>
      <createdate>5/25/2006 5:13:00 AM</createdate>
      <description>Group 2 Description</description>
      <membercount>868</membercount>
      <memberbulletins>False</memberbulletins>
      <membersCaninvite>False</membersCaninvite>
   </group>
</groups>
</user>

I truncated the top User tag, but it's the same as any other of the API's returns.

Does any one have idea when MySpace is launching thier REST API.