Debugging on the PIX will certainly give you a ton of information. With the PIX you can either use the "capture" command to capture all traffic based on an ACL (which can then even be saved off in Sniffer format, very useful), or in 6.3 code you can add a log keyword to the end of the access-list command.
See http://www.cisco.com/univercd/cc/td/doc/product/iaabu/pix/pix_sw/v_63/cmdref/ab.htm#1067755 for details, the default logging level of ACL lines is informational, so if you do "logging monitor info" then you should see these and not get all the other stuff you get at debug level.