Is your question actually more generic and is the old question why www. is or is not needed?
And if it is, why not read prior answers?
Hi - Everyone I have a website www.apnatimepass.com
which when i see in google webmaster tool has two version http://www.apnatimepass.com and http://apnatimepass.com
Now, My question is which one should i choose as preferred domain and do I have to submit xml site map to both.