Paypal is the online payment system owned and used by ebay - probably the largest in the world. Most people know about it, although you may occasionally get elderly people, or people who are not internet savvy who don't know what Paypal is. (I actually talked to a lady this week who said she did not use the internet, and did not have an email Acct. of any kind.) I use Paypal exclusively because it's fast and safe. I can usually complete a rental in 72 hours.
I do something very similar to Ron's process:
1. Invoice renter (email a Payal Invoice) and collect a $100 non-refundable deposit.
2. Put the official resort confirmation in the renter's name and send it to them.
3. Give renter 48 hours to confirm their reservation with resort.*
4. Invoice renter and collect the final payment which is due and payable: no refunds, cancellations, or changes.
*Only a handful of my rentals are Wyndham, so this works well for me, but with Wyndham it can sometimes take weeks to get the name changes out to the resort, so we usually ask the Central Reservations Rep to expedite the name change out to the front desk at the resort, so the renter can call and verify. Most are willing to do so, but some flat out refuse, just because they can.
Most renters are far more comfortable if they can call and confirm with the resort (or central reservations, for some systems) before they make their final payment. Many renters will call even if it's not part of your suggested rental process, and if the front desk doesn't have the reservation, they can become very nervous - so I try to make sure they have it BEFORE the renter calls.