Interrupt Service

Greetings,

I'm somewhat new to programming in C.

I'm using Keil uVision and would like some information on setting up interrupt routines.

I have setup my registers to interrupt on reception of serial data.

In C, how do I "name" or point to the interrup service routine?

I have surfed around and found possibly 2 answers:

void name interrupt 4
and
void name interrupt 4 using #

Can you recommend a good web site or web document that would explain this - I would rather not cut and paste for my solution but actually understand.

What is the "using" command doing - I can't find this information.

Thanks so much
-Sparky