Dolphin representative Darren Weiss explained that the Dolphin Sonar (download) partnership arose out of a limitation of developing for the iPhone. "Since there is no native voice API available for iOS, we decided to partner up with Nuance, leaders in the the voice-recognition space." Nuance is best-known for making Dragon Dictate, a PC-based speech recognition program. It also now owns several Android apps including Vlingo and Swype, and it contributed the main framework to Siri.
The app works just like the Android version. Long-press the gesture hand icon in the bottom left corner of the screen, then tap the microphone icon, or shake the phone while Dolphin is running. That will pull up the microphone icon. From there, speak the name of the site you want to go to or the search you want it to perform.
"Facebook CNET" instantly loaded the CNET Facebook page; "Share this" opened the Share options; "Google cheese" brought up search results. These were some of the same commands I tested on the Android version, and they worked just as well as on the iOS one.
One major difference is that Dolphin Sonar is a 99-cent in-app purchase for people with iPhones, but remains free on Android. The browser itself is free on both platforms, but the voice API on iOS isn't, said Weiss.