If you cannot download the H.Oda software here's what I would do...

If the heatsink seems glued on, it probably is. This would also indicate to me that it is a boxed processor. Early boxed Pentiums (that don't require a fan) have the speed printed on the side of the heatsink. If there is a fan, there are two clips that hold it to the heatsink. They are diagonal to each other. Pinch them both and lift the fan off the heatsink. Engraved on the inside of the heatsink will be the processor details.

If you cannot or do not want to do this, you can get a general idea of speed based on the ZIF socket. Socket 4 would indicate a Pentium 60 or 66. Socket 5 would generally be home to a Pentium 75-120. Socket 7 would likely be 133 and higher, but 75-120 can also fit.