> 1) Are any modems available to fit PCI slots? I know this isn't a
>    NetBSD question, but it's sort of related to the others:

Dunno.

> 2) Do I need to avoid Plug-n-Play modems for use with NetBSD?

I installed two Well 28800 bps p&p modems in a 486 NetBSD system, but
I disabled p&p and set the IRQ and IO address manually.  I never tried
the modems in p&p mode.

> 3) If I get a Plug-n-Play modem, how should I go about setting it up
>    to work with NetBSD?

Disabling p&p worked for me. ;)

> 4) Any models known to work particularly well with NetBSD?

The Well's worked - well, well. ;)  No problems with the two of them so far.
One modem is used as a permanent PPP link to the Net, the other is a dial-in
modem for PPP/terminal use.  No overruns even.

> 5) Any models known to lose particularly badly with NetBSD?

Dunno.

> 6) My main board currently gives me com0 and com1. If I get an
>    internal modem, will it use one of the existing two com devices, or
>    will it give me, e.g., com2? I assume the latter, but I just want
>    to make sure.

Whatever you want.  I configured the modems to com2 and com3.

> 7) What other questions should I be asking? What are the answers?

"How are you?" - "I'm fine, thanks - just a bit sleepy"
"What time is it?" - "It's 11:32 EET"

  -jm