How are you!
I'm using 2 computers with NETGEAR mr814v1
router(http://kbserver.netgear.com/products/MR814v1.asp, and dsl
router.( WireSpeed? Dual Connect NAT Router)

I use one cross-over calble and two patch cables. It works fine.
This my router configuration picture.
http://blogfiles4.naver.net/data14/2006/2/10/147/814-8395-jhwang2u.jpg

I'm wondering this configuration is O.K or not. Should I use 3 patch cables ?
According to manual, I have to use patch cables for each connection,
but my router works well so far. Can you give me some advice for my
router configuration ?

http://blogfiles4.naver.net/data14/2006/2/10/147/814-8395-jhwang2u.jpg

Your pictures are not loading.

Since the dsl modem will serve as a NAT router, the netgear is a bit
overkill.  A switch would work just as well in this configuration.

As for your configuration, I assume the patch cables go from the
router to your machines and the crossover cable goes from the netgear
to the dsl router.  This configuration is fine.  It may be that the
devices can autosense what's connected to the other end of the cable
and thus a patch cable may work instead of a crossover cable, but if
it's working now why change it?  A patch cable is the same as a
crossover cable except that with a crossover cable the transmit and
receive wires are flipped on one end of the cable.

Please try this..
http://blog.naver.com/jhwang2u/21744454

Question: Should I use 3 patch cables ?
  Yes you should because you improve perfomances

I have to agree with feldersoft that with that configuration you don't
need a second router inside the dsl modem; a switch would work fine.
Looking at the diagram you also don't need a crossover cable where you
have it, and the only reason it's working would be that the ports are
recognizing the crossover and autoconfiguring. However contrary to the
other comment a regular patch cable wouldn't be any faster.

I don't really agree that you should leave it that way and I would
probably change it for other reasons: first, if you forget that's a
crossover cable and you need a patch cable somewhere else to test a
connection and use the crossover one instead the results won't be what
you expect (most crossover cables are coloured differently for that
reason). The other reason would be that if you replace equipment at
some point and it doesn't autoconfigure it may take more time to
troubleshoot since you "know" the cable is good as it worked before.