I personally prefer using Rinkya.com, especially
for cels that are 40,00-100,000 yen or under
10,000 yen (they have a "cel sale" going on which
gives you pretty good discounts if you bid within
those ranges).  I also like the freedom of being
able to bid whenever you want without having to
e-mail someone first.  The catch with this service
is that you have to have a CC on file.  You place
a deposit with your CC in order to bid (it is
automatically refunded back to your CC, they just
do it to verify that the CC is working).

The other deputy service that I used which I
thought was really good was celga.com.  Their
rates are typically lower than most and I have not
had any problems with them.  Here they normally
make you pay half of your maximum bid amount
before they place a bid for you.  But, it is
automatically credited to your account or refunded
if you do not win the auction or if the bid ends
up much lower.

Hope this helps and good luck on bidding!!

Star Phoenix