Once you've found a drop shipper, go and set up an account. Different drop shippers have different setups but usually you can choose to credit your account, or, you can simply leave it empty and pay for each item as you sell it. Once you've created an account, all you need to do is grab the drop shipper's provided photos and product descriptions for the items you wish to sell and list them on eBay or your website (You will either be able to download the images from the supplier's site or be provided with a catalogue or CD containing images and product information). After you make a sale and receive payment, log into your drop shipper account, select the product you have just sold and take it through the checkout and pay for it. Enter the buyer's shipping details, and the drop shipper will package it up and post it.
Cheers!