the tyan tiger 100 has two isa slots but will only support slot 1 PIII up to 850 mhz and its discontinued. great board though......better advice is get a new modem and forget about isa. peace!
Tyan just came out with a Dual Athlon/Duron board capable of handling dual 1GHz processors, however it either only has one ISA slot or has eliminated them. Might be best to get a PCI modem, they tend to run faster.