Note:  MS Internet Explorer 7 & 8 has disabled Telnet which is necessary to bring up packet clusters.  Also Telnet is disabled in Vista (aren't you feeling secure?)!  The fix is here:  

http://library.osu.edu/sites/it/CSS/faqtips/ie7_telnet_fix.php  

Note: This file will change your registry.  If you are having an anxiety attack, all that I can say is that it worked for me.  If your machine goes dark and never runs again, please do not hold anyone responsible except yourself!  Registry changes are not for the faint of heart,

Telnet to a Packet Cluster

Telnet K8SMC  Jackson, MI

Telnet Telnet W8FT Findlay, OH 

Telnet K8AZ Chesterland, OH

There are also several web based clusters.  While they do not give you the almost instantaneous spots that the Telenet clusters provide, some do allow more elaborate filtering, so if you need JD1, you can set it up so only JD1 spots will be displayed.  Here are links to few that I have played with:

http://www.dxsummit.fi/DxSpots.aspx

http://www.dxwatch.com/