elec999: All mp3 "enhancements" are nothing more than a set of equalizer settings. Using an equalizer will create distortion in the sound output.
Westiegirl9: You can use rockbox firmware on your husband's ipod to allows bookmarks. In simple terms, it creates a new operating system for the player to run on. It's not as user-friendly, but it offers a ton more features. It's a fairly complicated process to load for most users, so if you're not too familiar with computers it would be a good idea to ask somebody more knowledgable in that area to help install it. Also, as a word of warning, it voids you warranty if you choose to install it.
Also back on topic, you can't upconvert a lossy file format ever. If you try you convert a 128 kbps mp3 made from a raw .wav file to a 256 kbps mp3, it's going to sound worse. This is because the source for the 256 kbps is the 128 kbps mp3 and NOT the raw .wav .