We’ve been telling our readers for some time now about Hotel Rewards by iDine — the fastest way to earn airline miles through hotel stays, bar none.

As with the more well-known dining program, Hotel Rewards simply requires that you set up an account and register a credit card (for free) at their website, http://www.idine.com .

At that point, you simply make your reservations with a participating hotel (they’re everywhere), and earn miles for every dollar you spend on that stay — generally five miles per dollar.

But now, through the end of the year, Delta SkyMiles members get a substantial bonus — triple miles. Through the promotion, you can earn a full 15 miles per dollar spent (For the mathematically impaired, that’s 1,500 miles a night at a mid-level hotel).

As an added bonus, members who combine their stay with a qualified dine at a participating restaurant will net an additional 500 bonus miles.

Our source at iDine says there are more improvements in the works.