At last count, the App Store featured something like 60 apps with voice recording capabilities. DAVA Consulting's iDicto happens to be among one of the better ones I've tried for simple voice-note-taking.
1voice recording
iPhone and iPad apps tagged "voice recording."
iTalk, It Listens, Voice Recorder from Griffin Technology
iTalk Recorder, according to Griffin Technology, the developer, is "WAY more than a voice recorder." That's partly true. Unfortunately, the "way more" part is still not enough to put it on par with many of the other voice recording apps in the App Store.
ITalk Recorder has one button recording.
