HT Games
Emulator Download
To play online Gameboy advanced games with multiple players, you need an emulator. Go to www.vbalink.info/download-gba-emulator.htm. You are presented with various options for GBA emulators.
Options
Choose the option that fits your needs. The site offers different downloads for two players, two to four players, LAN platforms, Wi-Fi options and a version to download to your hard drive.
Saving
Click on the link for the option you have chosen. Choose "open with" when the pop-up box appears. The file should be opened with WinZip or another unzipping program, as they are all zip files. If you don't have WinZip, you can get a free version at www.vodahost.com/winzip.htm. Once you have downloaded the file, unzip it and open the readme file.
Single-Player Sites
There are many sites that offer games, some are free and some aren't. If you go to www.home.lv/pokemon/gameboy-emulator.html, you can play online games without downloading an emulator. The same is true of http://gbemul.com.
Multiplayer Sites
To play with multiple players, you must have an emulator as shown in the previous steps. Then you must go to a site that has games that can be used in an emulator. The site www.gameboy-advance-roms.com/gameboy_advance_roms.htm lists websites that have games and other emulators you can download. For example, www.gameboy-advance-roms.com/go/to.htm?http://www.doperoms.com/ is one such site that was pulled from the list. Each site offers different games. They also offer technical support and user forums if you have problems. Go down the list and check out the sites.