I use my iPod for music, but it's nice to have some music on my phone on the rare occasions that I'm not carrying my iPod. EasyListening does the trick. I have a few Smart Playlists that collect 1GB of music together for my w910i. It's really nice to have access to my iTunes library in this way. Previously, I was manually copying files onto the memory card. Painful!

Also, support is excellent. I had one small problem that cropped up when iTunes 8 was released. The developer was really keen to track the problem down and fixed it straight away (within hours). This is what I love about independent developers (who care!).