Application Firewalls

http://www.applicure.com

http://www.axiliance.com (acquired by www.bee-ware.net)

http://www.bee-ware.net/

http://www.binarysec.com

http://www.bodacion.com/

http://www.breach.com/

http://www.checkpoint.com/

http://www.citrix.com (acquired www.teros.com)

http://www.denyall.com/

http://www.eeye.com/html/products/secureiis/index.html

http://www.elitesecureweb.com/

http://www.f5.com (acquired Magnifire, Watchfire-Sanctum)

http://www.imperva.com/

http://www.modsecurity.org/ (acquired by www.breach.com)

http://www.netcontinuum.com/

http://www.protegrity.com (acquired Kavado)

http://www.seclusion.ch

http://www.sentryware.com/

http://www.webscurity.com

http://www.whalecommunications.com/ (acquired by Microsoft)

Acceleration and optimization

http://www.bluecoat.com

http://www.cisco.com

http://www.citrix.com (acquired Teros)

http://www.f5.com (acquired Magnifire, Watchfire-Sanctum)

http://www.foundry.com

http://www.junipernetworks.com

http://www.nortel.com

http://www.radware.com

http://www.microsoft.com

http://www.nokia.com

http://www.netscaler.com (acquired by Citrix)

http://www.zeus.com

www.radarhack.com has put together a great list of resources about Web Application Security. This includes Application Firewalls,Acceleration and optimization,XML firewall

XML firewall

http://www.datapower.com (acquired by ibm)

http://www.reactivity.com/

http://www.forumsys.com/

http://www.xtradyne.com/ (acquired by http://www.prismtech.com/)

http://www.vordel.com/

http://www.sarvega.com (acquired by Intel)

http://www.layer7tech.com/

http://www.actional.com/ (acquired by http://www.progress.com/)

Related links
http://www.webappsec.org/
http://www.owasp.org/
http://www.cgisecurity.com/
http://searchappsecurity.techtarget.com/
http://www.sys-con.com/

News links
http://www.networkworld.com/topics/security.html
http://www.cio.in/features/

Interesting blogs
http://ha.ckers.org/blog/category/webappsec/
http://www.f-secure.com/weblog/

Security forums
http://www.astalavista.net
http://www.securemybox.org
http://www.governmentsecurity.org/