Can I execute a contract function by sending a regular transaction to the contract?

Question

I'd like to accept regular transactions to a contract and record a mapping address -> value. Is it possible to achieve it?

Answer 1

mapping (address => uint) data;
function () payable {
    data[msg.sender] = msg.value;
}

I think that would do it, but someone else should verify. The function without a name is the default function and handles any call that is not called on a named function.

Answer 2

Improving on Thomas Jay Rush's code (it's now missing the payable modifier as of 09/2016):

mapping (address => uint) data
function () payable {
    data[msg.sender] = msg.value;
}