Musical IC chip that I can tune myself / Kit?

You could do this with a Microchip, Inc. PIC10F206 or similar part. These are tiny six pin SOT-23 package parts that will run off a 3 volt lithium coin cell. About all you would need is a piezo-electric transducer and a short program and you are set. DigiKey Corporation sells everything you would need including an inexpensive programmer and the development software is free from Microchip. Good Luck!

Or a 16f84? I seem to remember that complete evaluation kits are available, but I can't remember the details.

There are a number of development cards that Microchip offers but I don't recall any that feature the 10F20x series of chip. The 16F84 is a much larger part. You could do it with pretty much anything it's just a matter of your packaging requirements.

My suggestion would be to use a PIC10F200 over the very expensive PIC16F84 (~ $0.50 vs $4.50. The 10F parts are available in very small packages (SOT23-6), have an internal oscillator and work down to 2 volts without ordering a special version. Especially important for a battery application the standby current is also much lower (100nA vs 1 uA). The programming tools are cheap too! Below is a link to this part. I hope this helps! http://www.microchip.com/stellent/idcplgidcplg?Idc Service=SS_GET_PAGE&nodeId=1335&dDocName=en019 863

Holmate Technology Corp. (Holtek) offers a Wide range of TO-92 Package Melody IC's that play up to 128 different notes. VERY simple to put into any project. Digi-key I think still offers them. HT-3813A-ND is a p/n for jingle bells. Search out HT-38 and see the list for yourself.