Disclaimer: Our HCH2 has the Nav system, so the non-Nav may be different.
On the screen, you'll have a bunch of tabs across the top: AM, FM, CD, Aux, and Card. Installing the Music Link adds another tab: "CDC". Literally, it thinks your iPod is a Compact Disc Changer. You don't lose the Aux port.
You'll have a cable inside the glove box that you plug into your iPod's dock connector. When it's docked, the iPod controls don't do anything, you have to control it all from the car stereo.
The head unit thinks there are 6 "discs" in the "changer". Selecting a different "disc" tells the iPod to do something else. Disc 1 lets you browse playlists; 2 is Artists; 3 is Albums; 4 is Genres. Disc 5 shuffles by Album; 6 shuffles by Song.
The head unit will not display track information (artist/album/song/etc.) It just shows you a track number which is really pretty meaningless.
So, if you want to actually search for something, you have to use a kludge called Honda Text-to-Speech. A CD-ROM comes with the package that will install software on your Mac or PC. Honda TTS will go through every song, artist, album, playlist, etc. in iTunes and generate an audio tag for it. It just uses the computer's speech synthesis to record an AIFF file with the artists' name, for example. It creates playlists to hold them all, and copies them onto your iPod. (Taking up a fair bit of space.) Once you've got the audio tags in place, you can use the <<, >> and >>| buttons on the car's head unit to work your way through the playlist/artist/album to find whatever you want. It takes a long time to generate the tags, and doesn't seem to be very bright in deciding what it needs to rebuild. You don't have to do the audio tags to use the iPod, only if you want to search. (So if you create playlists for the car, you should be okay.)
It's a kludge, and I'm keeping my eyes open in case someone comes up with a better solution.
There are 3 advantages to using it rather than the Aux port: it charges the iPod, the cables are hidden, and you can skip to the next song using the steering-wheel controls. The disadvantage is that it's embarrassingly stupid, and it's pricey, too. Installation is not very difficult, if you want to save some money. I would definitely NOT pay the $500 or so that dealers seem to be asking for the music link + installation.
You can read the user guide
here.