lots of questions ! Let's see...
I am not a qualified help in microphone matters, but the best thing is to start out with a test where you can check that your technical settings are all up to LV standard. You can read all about it here: https://wiki.librivox.org/index.php?title=1-Minute_Test1) The microphone I've used in conjunction with my computer is built into my computer (used for Skype calls). Is this sufficient?
2) If not sufficient, another microphone I have is a Zoom Handy Recorder H4 (that I've recorded my piano performances on). Would this work?
Please post the test in the Listeners Wanted forum: viewforum.php?f=21 and someone will check it and give you feedback or advice if needed. They will also tell you if the sound is ok.
these questions are best posted in the Help forum: viewforum.php?f=23 Lots of tech-savvy people in there that will probably answer them.3) If required to use my Zoom H4, should it be formatted to MP3, 44.1 KHz sample rate, 128 Kbps bit rate? Would it be better to use Low or Medium Mic Gain?
4) If required to use my Zoom H4, I've only ever recorded into the device's memory. Would I then be able to upload it to editing software (I see that you recommend Audacity)? Or is there a way to set up my Zoom H4 to the computer so that it automatically records into Audacity?
But yes, you need to somehow upload to your computer, and process it with an editing program, like Audacity (very recommendable, very easy to handle)
the computer fan also often makes noises. Best not to place the microphone too near the source of the noise. But with noise-cleaning you can also correct such background noise in the editing phase (if it's not too excessive). Another suggestion is: while the computer uploads, don't record, until it is quiet again.5) I've noticed that my computer occasionally makes a noise as if it's processing. I figured it would be good to download the text in case the noise is due to the Internet connection. Which download option is recommended (PDF, Full Text...), and would it allow me to "turn the page" soundlessly by pressing the right arrow of my keyboard?
Same goes for when a train or car passes by your house. Wait a bit, resume recording after it's quieter.As to what text you use, PDF or online or print-out version. This is as you feel best. You only need to read from the source text that is linked in the first post, we need to make sure everybody is reading from the same text.
because we want to limit server overload, we usually don't want anybody to download and listen to a work in progress, unless they are the prooflistener of course.6) Is it acceptable to listen to a PL-ok chapter of an in-process work I'm contributing to simply to hear the treatment taken by other readers, thereby allowing my interpretation to fit in better?
Since you are a new reader, I wouldn't mind if you listened to a chapter before recording though. But I don't think it's really necessary. What do you mean by "fit in better" ? Each chapter is on their own, read by another reader. Each have a unique way of reading and that is what is fun. As long as you are understandable (not too fast or mumbling, for example), it will be acceptable.
we have of all sorts. Also some use a cheaper microphone in the beginning until they know they are hopelessly addictedIdeally, I'd like to use my computer's microphone, as I use it for important Skype calls and don't want to mess anything up. Are readers able to get an acceptable quality from the computer's built-in microphone, or do they need to set up a separate microphone?
then often they invest in a better quality mic. But also here: if the technical settings and the volume are ok, and if the noise stays at an acceptable level, then it will be ok. This is no beauty contest. It should be fun. So I recommend: do the test and ask in the help forum.
And if you are set, come back and claim your first chapter, if you wish to start out with Richard Marsh. Good choice
Sonia
Sorry about that, but could you please insert that and reupload once more, please ? All the rest is perfect. 
