There seems to be a built in RSS by Category function that I’d never heard about or relized was available untill I started looking for one.
Here’s an example, just change the category id, found in Admin,Manage,Categories of your wordpress blog.
http://www.compareall.co.uk/travelodge/?feed=rss2&cat=3

53 URL’s to add to your ping list:
http://1470.net/api/ping
http://www.a2b.cc/setloc/bp.a2b
http://api.feedster.com/ping
http://api.moreover.com/RPC2
http://api.moreover.com/ping
http://api.my.yahoo.com/RPC2
http://api.my.yahoo.com/rss/ping
http://www.bitacoles.net/ping.php
http://bitacoras.net/ping
http://blogdb.jp/xmlrpc
http://www.blogdigger.com/RPC2
http://blogmatcher.com/u.php
http://www.blogoole.com/ping/
http://www.blogoon.net/ping/
http://www.blogpeople.net/servlet/weblogUpdates
http://www.blogroots.com/tb_populi.blog?id=1
http://www.blogshares.com/rpc.php
http://www.blogsnow.com/ping
http://www.blogstreet.com/xrbin/xmlrpc.cgi
http://blog.goo.ne.jp/XMLRPC
http://bulkfeeds.net/rpc
http://coreblog.org/ping/
http://www.lasermemory.com/lsrpc/
http://mod-pubsub.org/kn_apps/blogchatt
http://www.mod-pubsub.org/kn_apps/blogchatter/ping.php
http://www.newsisfree.com/xmlrpctest.php
http://ping.amagle.com/
http://ping.bitacoras.com
http://ping.blo.gs/
http://ping.bloggers.jp/rpc/
http://ping.blogmura.jp/rpc/
http://ping.cocolog-nifty.com/xmlrpc
http://ping.exblog.jp/xmlrpc
http://ping.feedburner.com
http://ping.myblog.jp
http://ping.rootblog.com/rpc.php
http://ping.syndic8.com/xmlrpc.php
http://ping.weblogalot.com/rpc.php
http://ping.weblogs.se/
http://pingoat.com/goat/RPC2
http://www.popdex.com/addsite.php
http://rcs.datashed.net/RPC2/
http://rpc.blogbuzzmachine.com/RPC2
http://rpc.blogrolling.com/pinger/
http://rpc.icerocket.com:10080/
http://rpc.pingomatic.com/
http://rpc.technorati.com/rpc/ping
http://rpc.weblogs.com/RPC2
http://www.snipsnap.org/RPC2
http://trackback.bakeinu.jp/bakeping.php
http://topicexchange.com/RPC2
http://www.weblogues.com/RPC/
http://xping.pubsub.com/ping/
http://xmlrpc.blogg.de/