many, but you can divide them in 2 categories:
with modchip
got a drive modchip (xenogc or duoq)? burn a minidvd with swiss.
got a ipl replacement modchip (hyperboot, viper and qoob pro)? boot swiss from the modchip.
got an ode or modchip that works like one (gcloader, wode, wiikey fusion or wasp)? copy the swiss iso to the sdcard.
without modchip
use pso exploit to boot swiss (bba needed, not recommended because is long and tedious).
use a wii or an already chipped gamecube to get one of the savefile exploits in the memory card (needs specific games).