Funds may take 30-60 minutes to show in your balance.
In some cases a Bitcoin transaction needs to be approved by the network before it can be completed.
The Bitcoin community has set a standard of 6 confirmations that a transfer needs before you can consider it complete. The more transactions on the network, the longer each transaction takes. Each confirmation is marked by the addition of a new block on the blockchain, following the one holding your transaction. The average time it takes to mine a block is 10 minutes, so you can expect a transaction to take around an hour on average.