The only MMX processors it will support are Overdrives. This is because it is not a dual voltage motheboard, and all MMX processors are dual voltage. The MMX Overdrive makes it possible by adding resistors on top of the processor, then using a special heatsink to fit over the resistors. The fastest Genuine Pentium MMX Overdrive is 200MHz. The 233 is not available as an overdrive from Intel, although several more expensive versions are sold by various manufacturers such a Kingston, produced from modified processors. So your next logical step is a K6-2 overdrive, again, these overdrives have their own resistors.
Additionally, your motherboard only supports up to 3x multiplier (3x66.6), meaning that, in all cases, you are stuck using overdrives, unless you want to go with a Pentium Classic 200 or slower. I would go for the overdrives!
BTW, the Pentium MMX 200 Overdrive cost about the same as the Pentium Classic 200, between $40 and $50. Faster AMD overdrives are a little more pricey.