Microphones and beats

The best way to tell if they are any good is to listen to them.

Plug 'em into the "mic input" of your soundcard, and record yourself reading or singing. Then repeat with the other one.

... I'm not sure what you mean "how to use them". If you mean "what type of recording are they best suited to", then that'll mostly depend on what they sound like.

The silver one looks like it has 2 plugs. The larger of the 2 will be the audio out, the small one will be for pausing a cassette recorder, using the switch on the mic.
I wouldn't expect this one to sound too great, it was probably a cheap mic that came with a cassette recorder for taping people talking.
(that part number looks like a Radio Shack part number to me.... Google-de-Google... Yup, it is. )

And the other one.
A bit of googlage identifies the F-V220 as a Sony mic that can be bought new for less than $20.
It's probably the better of the pair, but I wouldn't expect great things from it.

Errr, but they don't turn on. Neither of them works when I plug it into my comp. They got switches on them, but I don't know how to give them power.

You shouldn't need to "power" them - they're not condenser mics.
They should work when you plug them into the sound card in your computer. What you do have to ensure, is that the microphone channel is activated, in the Play Control (Options, Properties, Recording).

If you have an adapter you can plug them into the (clean channel) input of a guitar amp to test if they even work.

Turn the input level down to 0, before plugging in, and then turn it up s-l-o-w-l-y.

And as I said before, the switch on the silver one probably doesn't turn the mic itself on/off. It's to pause a tape recorder that is plugged into the smaller plug.

Hmm, I guess they don't work. The head phone mic works, so the channels probably on, and I don't have an adapter so I can't test them out, I'm afraid. Thanks for the help.

Any tips on that beat program?