I have RCX 1.0, what more do I need?

Hi all.

I have recently come into possession of an RCX 1.0 brick (the one with the power
socket), but nothing else that would come with it. What other things do I need
to purchase to make my new brick useful?

I understand that at the very least I will need an IR Tower so that my computer
can communicate with the brick. From what I've read, I should be able to use the
USB version of the tower that came with RIS 2.0 [is this correct?] (I'm much
more familiar with USB than I am with serial ports - I'm not even 100% sure that
my computer even _has_ a serial port!). I know that I will need to install some
form of software that will let me interact with the brick, but I am unclear as
to exactly what is required. I can think of three fuctions that will need to be
taken care of: some form of development environment where I can write programs;
a driver for the tower so that I can pass these programs to the RCX; and
firmware that will allow the brick to execute the programs. I've read terms like
ROBOLAB and BrickOS, but I don't know which software performs which function,
nor whether I can download everything I'll need from the Internet or if I'll
need to source a copy of the original CD with drivers etc.

I did find this thread from last year
http://news.lugnet.com/robotics/?n=27598
which I think goes some way to answering my questions, but I'm still confused
because I'm unsure of how all the components of the software work together.

I also know that without sensors of some description I'm going to be very
limited in what I can do. I'm ok with that. :-)

Of course, one possibility is to simply purchase a RIS 2.0 kit. That way I'd at
least have all the basics, with the added bonus of two RCX bricks. However, if I
can get away without spending that much money I'd be happier.

I'm running Windows XP, which seems to have some problems running the original
software, but I can cross that bridge when or if I come to it!

Thanks in advance for your help.

Owen.