PowerPC ?..If your PowerPC-enabled Mac has Airport Exterme card then you could use Linksys WRT54GS or G [with AfterBurner] *requires 3rd party firmware......So you could take advantage of 125Mbps SpeedBooster that Airport offers [Bear in mind , it uses a Broadcom BCM404x Card that supports AfterBurner and its enabled by default on the mac]

If you're using Intel mac , any router would do @