Additionally, the free Shazam app now offers a subscription model upgrade to the paid version, which allows for as many tags as you want, extra features like "Drive and Tag," and more information about the songs you hear with the app. For a limited price of $2.99, you can get access to Shazam Encore for an entire year, or for $4.99 (the price of the paid app on the App Store), you can get a "lifetime subscription." Clearly Shazam wants to offer something a little cheaper for customers who aren't sure if they'll use the app that much, but honestly, if you want the pro options, the Encore version is worth the $5.
On the other hand, all I've ever had is the free version, and for the occasional "hear a song on the radio or in a store and wonder what the heck it is," Shazam has served me quite well. Good to know it'll now look and run better on the iPhone 4.