declaring Hex in python

[PythonAnimal at gmail.com]

I want to use some old C code such as
#define GEN_STREAMTYPE_NULL          	      0x51
I need to send this to a server, but it must be declared as a unsigned
four byte constant.  I can not just send a string.  I love python, but
am looking for information where I can declare this and then send it
through a socket.
Also are there any classes or methods which can manipulate what is
returned, such as shifting bits returned.
Thank-you