Here's a pic of what it was. You can see the ribbon coming off the top that is the input. It has 8 pins if you look at the green side of the first pic you can see the 8 solder marks. I do have a multimeter I do not really know how to use it though.
This actually shouldn't be a very hard mod. You just need to find the positive and negative voltage ends then wire up a 2 pole mic to those prongs. If you want to make the mic removeable, then get yourself a mini-stereo plug (both male and female ends) then wire it up the same way.
If you go the mini-stereo plug route, then let me suggest that you use a powered lapel mic. I switched over to using that just before SDCC last year, and although the mic was like $25 it was a great investment. I'm still running on the same battery I bought it with, and It's pretty loud.
Did the mic original mic have any batteries or just plug right in? If it just plugs in without it's own batteries, as said you can probably just use a 2 wire mic and try touching the pins. (disclaimer here - always use caution with electronics, AC for sure). This is battery powered though right?
Read about continuity. If you set the multimeter on the continuity setting, you can see if 2 leads are physically connected in the circuit. Usually the meter will make a sound to show this. Make sure the cables are plugged in COM (-) and V~ma.
The ribbon has a white stripe, probably the ground wire. Not sure about 8 pins though.