Even the FBI and Packet Storm are posting software to attempt to detect such attacks, although it appears that software is only appropriate for use on Unix/Linux machines.
Regardless of what platform you run, Gibson Research's Shields UP! will test your computer's vulnerability.
You may not think your computer is vulnerable, unless you read Fred Langa's WinMag article The Four Myths of Online Security.
You may want to install some sort of Firewall to block attempts to probe your computer. One free firewall is Zone Alarm 2.0, but there are others such as ConSeal PC Firewall ($49.95 - Win9x / $150 NT Wks / $295 NT Srv), SyShield ($29.95 for Win9x and NT), Norton Internet Security 2000 ($59.95 for Win9x ONLY!), and BlackICE Defender ($39.95 for Win9x and NT), all of which are discussed very well on http://grc.com/su-firewalls.htm.
Earlier report with traceroute details of an attack I experienced.
Previous TCS Virus Alerts: