Who receives the fees?
Miners receive the transaction fees in additional to newly mined bitcoins. This is to ensure that mining (which is necessary for the security of the network) will still continue even after all 21 million bitcoins have been mined, with mining then being supported entirely by transaction fees.
Is this an income opportunity?
Yes, anyone can mine, though powerful hardware is required if you expect to make a decent amount, and you have to consider your electricity costs as well. Mining is not a get-rich-quick scheme, and in fact you are likely to make a net
loss unless you have very cheap electricity or specialised mining hardware.