how to obtain proper 'call back URL' I have installed drupal 7 using MAMP and following this tutorial to configure drupal with oAuth, 

While adding consumer I tried call back URL with domain name like http://mastmobilemedia.com/oauth/request_token which gave http status 404 error in browser , when i tried with IP Address http://192.168.1.4/drupal/services/xmlrpc ( as i found in one of the sample code) i got page not found error in browser

so please can anyone help me in knowing what is the proper call back URL to be specified ? how to get client side URL ?
You are getting 404 error because actually there is no page in your site with that url.

In your referenced tutorial the following statements can found as a note:

"
Note: The sample callback URL above is incorrectly shown. The callback URL should be an URL on the client side. When Drupal has authorized the consumer, it will call this URL with the access token as a parameter."

So you have to define a page call back with path as you want. You can define in your custom module.  OR You can give a valid site path as callback url. So When Drupal has authorized the consumer, it will call this URL with the access token as a parameter.