Yes, it's possible.
You can use any PORTB pin to do this. Just generate an interrupt with every turn, and count the pulses. Calculate the time between two pulses and you're done.
Assuming your RPM meter will sense speeds up to 20000 RPM:
20000 RPM = 333 revolutions per second
And the period of the revolution would be 3 ms.
If you run the PIC with a 4MHz crystal, you will have an instruction every 1 us, and this will be your resolution
Hope that gets you started
Cheers