Can I use the credit cards of Indian banks in other countries?

As per my knowledge, I have heard personally that a debit card of Indian bank has been used in US for purchase of laptop by one of my friend(who is also an employee of Indian Bank) and I hope if debit card is valid, then there must be credit card use too. Nowadays anything is used online, even this can be used for any on line purchase.

Yes Credit can be used in any country. But your card must have either VISA or MASTER logo which is accepted world wide.
There is no additional procedure need to follow. For example you are having ICICI bank credit card and you are at USA then after purchasing some grocery you just give your card and they will swipe and the amount will deduct in USD ( Us dollar) and your statement will show you in INR ( Indian rupee) by converting that day value.
About extra charges if that card is not Global card then you will be charged of Rs 150 per swipe ( what ever amount you spend).
So for International travel banks has been designed a new credit card which does not charge you anything extra rather than your actual expenditure.