The 90% of online casino accept deposits and withdrawals of the wins through credit cards (Visa, MasterCard etc..), but almost never through American Express.  
If you own an American Express credit card, the instructions below will show you how to deposit.  

1. Open an e-wallet account such as Click And Buy  
2. Deposit on the e-wallet account with your American Express credit card   
3. Click on the cash desk of the casino or online poker  
4. Enter in the deposit section and select Click And Buy  
5. Select the amount to be deposited on the account of the casino or poker  

This system works in all the casinos that don't accept American Express credit cards, but it is also worth for any other credit cards. A lot of people use e-wallet so not to give their own personal dates of the credit card to the casino, to play more safety.   

We recommend you to play in the following safe casinos: Tropez Casino (critique Tropez Casino), Spin Palace Casino (critique Spin Palace Casino), Europe Casino (critique Europe Casino), Euro Grand Casino (critique Euro Grand Casino).