Processor Question

I have a quick, and stupid, question. Basically, I need to know where my Celeron falls in line with the Pentiums and AMDs of the current world. Most of the programs that are coming out now adays are coming close to the processor size that I have but they are asking for PIIIs as a requirement. Would I be able to run these programs as long as I have at least the same size processor or does the class matter? If this doesn't make any sense let me know and I give an example of what I mean.

 

How fast is your Celeron? Some of the old ones are 300mhz and less, new ones are up to 1.2 GHz. Class does matter, a Celeron 600 isnt as fast as a P3 600, and some Athlon 1.4's are faster than some P4 1.8's.