APEWS is just an automated system, if spam or spam involvement (hosting spammers, selling spamware) from your IP address/range ceases, it will drop out of the list in time. Normally the listing involves spam related problems with your host and the first step you need to take is to complain to them about the listing, in almost all cases, they are the only people who can get an address/range out of the APEWS list. If there is a spam related problem with your host, their IP address/range will not be removed until it is resolved. If your host or network is certain a listing mistake has been made, ask them to read this FAQ, do not post messages yourself about apparent errors in the listing of your provider.
The network owner (and no one else) can then post a message in a public forum mentioned above with the APEWS record number (eg. E=211497) and/or the IP address/range/domain information in it. Placing the text "APEWS:" in the subject can help a APEWS editor or developer see the message and they may double check the listing - note that, although others may, no APEWS editor or developer will ever reply to the posting. Will this get your IP address/range removed from a APEWS listing? Again, not if there are currently spam related problems with your host.
Whatismyipaddress.com does not recommend the usage of this blacklist. It has the potential to block large segments of IP addresses. If you are listed with them it is generally not a problem.