Can I use Fasm to write a program that uses the 8087 c0-processor? If so how? Can you show me an example?

I don't know if it makes any difference whether its a co-CPU or integrated into it. The FPU instruction-set should be the same. Somebody correct me if I stand wrong here...
http://courses.ece.uiuc.edu/ece390/books/labmanual/inst-ref-general.html#INST-REF-F2XM1
...and look down from there

wow, there is something like 8087???

8087 was the first model of FPU for PC computers, in times when the FPU was in form of co-processor (additional processing unit you could plug into the motherboard). And yes, the instruction set is the same no matter whether FPU is a co-processor or is integrated into CPU.

In fact the encodings of FPU instructions are affected by the fact that they initially were instructions for the separate unit, as they are were in fact single ESC instruction of 8086, which escaped the command out to the co-processor, and the interpretation of escaped code was done by that separate unit - thus you possibly might have different co-processors with different instruction sets, but I have never heard of any instruction set for 8086 co-processors other that 8087 one.

hmmmm, isn't ESC opcode 0F, which was pop cs on 086?

No, 0F is just the part of two-byte encodings, it has no memonic itself.
The ESC instruction used opcodes D8-DF.
Quick description of ESC: http://library.n0i.net/hardware/i8086opcodes/#ESC