Hi Jim Jam,
this is wthat i am using exactly in my project for getting results. https://ap2.salesforce.com/services/data/v20.0/query?q=select FirstName,LastName,Phone,Email from Contact where FirstName LIKE '%a%'   I think the problem is in sandbox account creation can u please help me is need to give any permission for that account .

Hello,
I am using below api call in my project "https://ap2.salesforce.com/services/data/v20.0/query?q=select+FirstName,LastName,Phone,Email+from Contact where+FirstName+LIKE+'%a%' "
but i am get  400 bad request error can you please any one help me to resolve that 
i have created a Connected app in my sandbox account 

Note: its working for one of my old account, earlier i created one new sandbox account with that i am getting bad request error

Hello,
I am using below api call in my project "https://ap2.salesforce.com/services/data/v20.0/query?q=select+FirstName,LastName,Phone,Email+from Contact where+FirstName+LIKE+'%a%' "
but i am get  400 bad request error can you please any one help me to resolve that 
i have created a Connected app in my sandbox account 

Note: its working for one of my old account, earlier i created one new sandbox account with that i am getting bad request error