EMULATORS

VISUALBOY ADVANCE

VBA LINKING VERSION

visualboy advance is a gameboy advance emulator that emulates gameboy, and gameboy color games as well. it is very compatable with most roms that you may find. there is also a linking version, which can be used to link the VBA over a LAN, or on the same computer. there is no internet play available for the VBA that i know of......
gens is a sega emulator, that emulates the genesis, megadrive, sega cd, megacd, and sega 32x emulator. this emulator is capable of internet netplay, using kaillera. it can also be used for LAN multiplayer games as well, but the kaillera server download is needed
jnes is a nintendo entertainment system emulator. it emulates most of the nintendo roms available. this emulator is capable of internet netplay with via kailerra, and LAN play with the kaillera server
project 64 is a nintendo 64 emulator, with some of the highest compatibility rates of all the N64 emulators out there. it also uses a plugin system so you can get the best performance out of the type of games that you want to play. netplay is not available on the original project 64, but there is a modified version called project 64k that utilizes the kaillera client to netplay games. as with all emulators that use kaillera, to play over a LAN, you need the kaillera server.
zsnes is a super nintendo entertainment system emulator. it emulates most SNES roms that i have found pretty well. this emulator supports netplay over a LAN, but there is no support for internet play
pcsx is a playstation emulator, that emulates pretty well, with the right plugins. this emulator depends on plugins, and a bios in order to run. this emulator theoretically has netplay capabilities, but a specific plugin is required.
KAILLERA SERVER
this is the site for the kaillera server required to play LAN netplay games. the readme file pretty much explains everything that there could possibly be to explain about it.