Legitimately, not sure, Apple [and an increasing number of other Mac developers] seem increasingly keen to ditch any mention of "System Requirements", let alone *themselves* keeping legacy PPC versions on their servers.
But, please don't do the technically *illegal* thing and download a fully functional version from a BitTorrent site. iWork '06 and '08 work fine on PowerPC, there are pirate version on BitTorrent sites out there and downloadable within the hour, but please don't do that, since that is piracy and that's illegal. Sorry that there's no legal way to get a PowerPC version of iLife these days, other than of course doing the *illegal* thing and pirating it.