The TwitPic.com website has a webservice API which will post a photo to a user's Twitter account along with a short message. You can use the download manager to upload a file. Even though it is called the download manager it has a method to upload files as well using HTTP POST.
this.controller.serviceRequest('palm://com.palm.downloadmanager/', {
method: 'upload',
parameters: {
'fileName': filename,
'fileLabel':'media',
'url': 'http://twitpic.com/api/uploadAndPost',
'contentType': 'image/jpg',
"postParameters": [
{"key":"username" , "data": username},
{"key":"password" , "data": password},
],
"subscribe": true
},
onSuccess : function (resp){
Mojo.Log.info('Success : ' + Object.toJSON(resp));
},
onFailure : function (e){
Mojo.Log.info('Failure : ' + Object.toJSON(e));
}.bind(this)
});