List of parts with Mouser part numbers.

The hard part to obtain is the Transound capsule. The good news is that as of April 2005 we have a supplier for small quantities - details here.

Also, the 1Gohm resistor (yes, that's 1000 Meg) can be hard to find, and is usually expensive (more than $3 each). If you're looking at a different supplier, check for the 1Gohm resistor first. Mouser does carry them, and Digi-Key sometimes has them as MOX200J-1000ME-ND. I'd recommend the MOX200J if you can get it, since it is the size of a regular 1/4watt resistor.

Quantity Part Description Mouser Notes
1 2N4416A FET 610-2N4416A
2 2N5087 PNP Transistor 610-2N5087  
1 78-1N5242B 12V Zener Diode 512-1N5242BTR  
1 6.8K Resistor 271-6.8K  
2 100K Resistor 271-100K  
1 330 Resistor 271-330  
2 2.2K Resistor 271-2.2K
1 1G Resistor 588-MOX-750231007F These tend to be big
1 10uf Electrolytic Capacitor 140-XAL35V10  
2 0.47uf 50V Polyester Capacitor 140-PF1H474K  
1 100uf Electrolytic Capacitor 140-XAL35V100  

Original list by Keith Luke, updated by Scott Helmke