Plz help, iphone4 not showing name of the contact

[j.iphone4]

i am new to the iphone and have an iphone 4, i copied all sim contacts to iphone memory. when some1 calling me iphone not showing their names it shows just number infect that number saved in my contacts, plz tell me what to do, somebody instructed me that if i update my contacts number to international format then it will work for exmpl 03451234567 to international format = 0092345123456 confusion is that i have over 400 contacts in my iphone4 now how can i update all the 400 contact to international format plz help me what to do.