|That card was issued in 1998 and is compatible with Windows 95 and Windows 98.|
The easiest way to install it is to plug it in, boot Windows 95. It will detect the card and prompt you for the drivers which are on floppy. Point it to the A: drive and load the drivers. Then go to Control Panel and reinstall TCP/IP so it can correctly configure the adapter. (This requires the Windows 95 disc/disks). Then reboot and you should be online.
iMac G5 1.8GHz "Hero" PowerPC
2 x 1GB DDR PC3200 SDRAM
160GB WDC WD1600JD-40GBB2
Mac OS X Leopard Version 10.5.8