Seems like any special characters sent to the MySpaceID REST endpoints are replaced by HTML entities. URLENCODING or HTML entifying the status text before doesn't help. Nor does escaping via addslashes do any good.

I can confirm this issue for the StatusMood endpoint.

array (                                                                                                                                                                                        |~
  'sbs' => 'PUT&http%3A%2F%2Fapi.myspace.com%2F1.0%2Fstatusmood%2F%40me%2F%40self&oauth_consumer_key%3DXXX%26oauth_nonce%3D7806149244e4c6da1a7e1e7.57013564%26oauth_signature_method%3DHMAC-     |~
SHA1%26oauth_timestamp%3D1313631649%26oauth_token%3D22MGCZWIYo2AP02ytBgTNGTKmU%252B5jEAiE98R97X3pwT265GxXdFM9h2cggTtBXlaANkZQGKjmIMihIg6LBIOhi3LPxosky2VbVwgp6%252FUeeY%253D%26oauth_version%3D1.0',                          |~
  'headers_sent' => 'Authorization: OAuth oauth_consumer_key="XXX",oauth_signature_method="HMAC-SHA1",oauth_nonce="7806149244e4c6da1a7e1e7.57013564",oauth_timestamp="1313631649",               |~
oauth_version="1.0",oauth_token="XXX",oauth_signature="FEmYljWjzMIXBfT9TW0aWjZAXDg%3D"^M                       |~
Content-Type: application/x-www-form-urlencoded',                                                                                                                                                                             |~
  'headers_recv' => 'HTTP/1.1 200 OK^M                                                                                                                                                                                        |~
Cache-Control: private^M                                                                                                                                                                                                      |~
Content-Length: 95^M                                                                                                                                                                                                          |~
Content-Type: application/json; charset=utf-8^M                                                                                                                                                                               |~
Server: Microsoft-IIS/7.5^M                                                                                                                                                                                                   |~
X-Server: 4fdfa65375fdd1d2775c0dbbc57441f7facde86fb4323b97^M                                                                                                                                                                  |~
X-PoweredBy: Duh! Winning!^M                                                                                                                                                                                                  |~
Date: Thu, 18 Aug 2011 01:40:50 GMT^M                                                                                                                                                                                         |~
Connection: keep-alive',                                                                                                                                                                                                      |~
  'body_sent' => '{"status":"Daft Punk - Live Mixes 2007 (B1 Mix)","source":{"name":"SAM Song Info","imageUrl":"https:\\/\\/www.sam-song.info\\/favicon.ico"}}',                                                              |~
  'body_recv' => '{"statusLink":"http:\\/\\/api.myspace.com\\/1.0\\/statusmood\\/myspace.com.person.565601155\\/@self"}',                                                                                                     |~
)

That's the OAUTH debug Info including the requested URL and the PUT body (JSON) (Tokens and Keys replaced by XXX)