On February 2, I posed a question about uploading digital pictures from
my computer to the compactflash card in my Canon PowerShot A40.  It
was never answered so I pose a new question (in direct response to
your request for clarification - nishka-ga): What should I look for
when shopping for a compactflash card reader?  Though my laptop is old
(4 years) and does not support USB 2.0 nor Firewire, I intend to buy a
new computer within 3 months so it would be nice to find a card reader
that will work with my old and new machines.  I am simply looking for
some solid buying guidelines.

Seeing as you haven't received an answer yet I thought I would give a
comment.

Does your laptop have a PC Card interface (formerly known as PCMCIA)?
If yes then you could get a PC Card to CF Card adapter.  They are much
cheaper than USB or Firewire adapters.  Also they are faster than USB
1.1 adapters.  Of course you need a PC Card slot to use it so you
can't use it on a desktop computer.

The speeds at which you average CF Cards can be read or written to is
close to the speed of USB 1.1.  So USB 2 or Firewire is not going to
give you a massive increase over USB 1.1.  However having said that
USB 2.0 is backwardly compatible with USB 1.1.  So if you buy a USB
2.0 adapter it will work with your old laptop and you'll get a slight
increase in speed with your new computer.

I noticed in your first message that you were have problems with
Canon's Zoombrowser software.  Canon have recently released a new
version of the software that is lot better than previous versions. 
And whats more it is a freely avaliable upgrade if you have a previous
version of Zoombrowser.
See the following webpage for more information.
http://www.powershot.com/powershot2/customer/zoombrowser.html