2 Lan cards in a single CPU unit

yes it is possible.with 2 IP

Yes.

Depends on what you are trying to achieve however.
You can mix the cards if you are accessing different networks. If you want some kind of team / failover then they must be the same.

Most windows versions only work correctly when one default gateway on one LAN card. You need some kind of routing to achieve any more. Like Routing & Remote Access in 2000 / 2003. You effectively turn your Computer in to a router.

Yes it's easy to do the only thing that you [b]Can Not[/b] do is mix the LAN Card types so you'll have to either use 10/100 TBase or Gigabite LAN Cards you [b]Can Not[/b] mix a 10/100 TBase & Gigabite type LAN cards though as the system will not work. If you already have an On Board LAN you'll need to use the same type of LAN card to allow the system to work.

Col

yes, especially if you want to bridge 2 networks together. use 2 different brands if possible to avoid confusion.