Have you ever been frustrated when you ask a client for a high-res logo and they keep sending you thumbnails? A lot of you have probably been in a situation where you could really use a vector logo, and your client can't deliver.
Best Brands of the World (brandsoftheworld.com) is an online treasure trove of vector logos. There you'll find thousands of logos for big name companies and small ones alike. There are even logo variations for the big brands. In other words, you might even be able to find event-specific logos, and specialty logos.
All of the logos you find at brandsoftheworld.com are free and come in EPS format. So, the next time your doing an event poster sponsored by Pepsi, you don't have to rely on the client for the Pepsi logo, however, it's always wise to get the logo approved before using it.