Know your ipaddress at itsyourip

DNS related

Dnsstuff
Global Whois Tool
Dnsreport
Dnstools
Pingability
DNSdoctor
Name Server Zone Transfer Tool
MyDNSConfig
Lookup Server

Online dig tool for dns

Online DNS Dig Tool
Web host select online Dig Tool

Network management tools

Nagios
Cacti
Mrtg
Munin
Rtg
Argus
Jffnms
Zabbix
Healthmonitor
nPulse
BandwidthD

Backup

Bacula
Amanda
Rdiff
Rsnapshot
Rsync
Flexbackup
Dump
Abakt
BackupPC
Dirvish

Ip Management Software

Phpip
IPplan

Centralized syslog

Syslog-NG
Rsyslog
Modular Syslog

ISP Control Panel Software

VHCS
ISPConfig
Syscp
Ravencore
Alternc
Hostingsoftware
ISPman
Yupapa
Acctmgr
Domain Technologie Control (DTC)

ISP Billing Software

gcdb
cwISPy
MiniBill
ispbs
MadBMS
Freeside
CitrusDB

Mail servers

Qmail
Postfix
Sendmail
Exim

DNS servers

Bind
Djbdns
Dents
Xyria
Powerdns

Groupware

Simplegroupware
Moregroupware
Synergy
Conflux
eGroupware
Hipergate
Tent
Opengroupware
Groupoffice
Trac

Proxy Servers

Proxy
Oops
Squid
Phpwebproxy
FFproxy

Anti-Virus

Clamav
F-port
Bitdefender
Openantivirus
Aegisantivirus

HTML Editors

Quanta Plus
Nvu

FTP servers

PureFTP
ProFTPD
mtftpD
bftpd
MySecureShell
moftpd
vsftpd
TwoFTPd
WU-FTPD

FTP Clients

PHP FTP Client
Kasablanca
Secure FTP
Web-FTP
net2ftp
phpftp
WTP

Web Servers

Apache
japach
Lighttpd
thttpd
Mathopd
Boa
Jigsaw
CERN httpd
Webrick
CL-HTTP
Cherokee
Yaws

Hard Disk Cloning

Ghost for Linux
PartitionImage
g4u
SystemImager
CloneIt
hdimage

Wiki software

ChuWiki
DokuWiki
ErfurtWiki
Flexwiki
Instiki
Kwiki
MediaWiki
MoinMoin
OpenWiki
PmWiki
PhpWiki
PikiPiki
TiddlyWiki
TikiWiki
Twiki
UseModWiki
WackoWiki
WikkaWiki
XWiki
Zwiki

ERP And CRM Software

Tiny ERP
FacturaLUX
CK-ERP
OpenAspect
Dolibarr
EGS
ONess
Sequoia
Compiere
OneMaxx
FreerP

Instant messaging servers

ejabberd
IServerd
xmppd.py

Web browsers

Amaya
Epiphany
ELinks
Galeon
Konqueror
Links
Lynx
Mozilla Firefox
Mozilla SeaMonkey

Publishing

Passepartout
Scribus

Password management

Ked Password Manager
KeePass
Password Safe
PINs

Password generators

APG
SPG
Mpm
Pwg
Password Creator
Passook

Antispam Software

AntiSpam-filter
tarpit_antispam
Sagator
POPMail
CRM114 Discriminator
Quick Spam Filter
Maildrop Spam Filter
DSPAM
Spamikaze
SpamAssassin

CAE

CAELinux
Code-Aster
Elmer
Impact
Salome
jCAE

Encryption

CrossCrypt
GnuPG
NeoCrypt
Seahorse
TrueCrypt
bcrypt
PGP

Text Editors

Acme
Bluefish
Elvis
Gedit
GNU Emacs
gPHPEdit
jEdit
Katoob
KWrite
Nano
NEdit
Vim

Middleware

Geronimo
Jakarta Tomcat
JBoss
JBoss jBPM
Mule
ObjectWeb JOnAS
ObjectWeb JORAM
ObjectWeb C-JDBC
ObjectWeb Celtix
ObjectWeb Shark
ObjectWeb JOTM
ObjectWeb OSCAR
ObjectWeb ProActive
ObjectWeb Speedo

Image viewers

Cat-Photo
imgSeek
Imgv
Java Image Browser and Sorter
JImageView
Image Viewer
views

IDS (Intrusion Detection System)

Snort
Tripwire
Rule-based IDS
Tiger security tool
AIDE
ViperDB
Integrit
Armed

Protocols analysing,sniffing

Ethereal
Tcpdump
Etherape
Ntop
Snort

Security scanner

Nessus
Nmap
Network Security Analysis Tool 
Sussen
SystemSearcher

IP-telephony

GNU Bayonne
Openh323

P2P file sharing

Azureus
BitTorrent
BitTornado
DC++
eMule
Freenet
giFT
Gnucleus
GNUnet 
Hydranode
Lime Wire

Mortgage Calculators

Mortgage & Loan Calculator
PHP Mortgage Calculator
Mortgage Calculator Plus
mcalc

Forums

Forums
vtiger
SiteNet BBS
Quicksilver
GrimForum
phpBB
vbulletin
punBB
Sniz Forums 2000

RSS Feed Generators

RSS Builder
Tiny Tiny RSS
RSS Mix Tape
RSS Writer class
instantRSS
FeedCreator

Video editing

Avidemux
Cinelerra
GNU VCDImager
Jahshaka
Kino
VirtualDub
LiVES

Television

Freevo 
K!TV 
MythTV
tvtime
xawtv

PDF Viewers and Creators

Evince
Kpdf
ViewPDF.app
ghostscript
pdfcreator
pdftk
reportlab
xpdf

Insurance Software

CC-Manager
Home Insurance Inventory Wizard
Freemed-YiRC

Todo List managers

Motodo
Tudu Lists
ukolovnik
phpTodo
ToDo Manager
PHP 2 Do
TAF
QTodo
Tux ToDo
Agnostos
ackerTodo
PHP TODO
WebTodo

File Splitters

TkSplit
KJSplit
Psplit

Software License Management

phpLicenseWatcher
Application Distribution Licensing System
Software License Audit
License Tracker
lGen

Mind Mapping

Freemind
View your Mind
KDissert

Astronomy

XEphem
Xplns
Qastrocam
avsomat
KAstrHorloge
Lin4Astro

PhotoAlbum

Simple Photo Album
Web Photo Album
Atomic Photo Album
iPhotoAlbum
Slooze PHP Web Photo Album
yappa-ng
zphoto
A-Gen

Plotting

Gnuplot 
Grace
LabPlot
QtiPlot
SciGraphica
XyVue
pyglplot


DVD Rippers

QuickRip DVD
Lxdvdrip
DVDRipper
FooRipper
Thoggen

Learning support

ATutor
Dokeos
ILIAS 
Moodle
OLAT
Sakai

Webcam Software

webcamserver
sn-webcam
Cacam
eCam
camE

Workflow Engine

Bonita
OpenWFE
OpenSymphony
SWAMP
con:cern
Taverna
Bossa

Expenses Management

Simple Expenses Manager
j2Wallet
Cash2ME 
Money Share
SharedExpenses
Sigma Expense

Document Management

DM
SmartDms
WDMS
yaDMS
DocumentManager
Eidetic DMS
openPro

Screen savers

Electric Sheep
Flurry
XScreenSaver
Boinc

Journal Software 

eJourn
Article System
atengine
Discloser

Build Management

luntbuild
Invicta
Vesta
Caterpillar

HR(Human Resource) Management

Electronic HR Management System
OrangeHRM
Open Source HR Information System

Scanning probe microscopy

Gxsm
Gwyddion

window managers

Blackbox
Evilwm
CTWM
Fluxbox
HaZe
IceWM
Ion
Openbox

TeX software

AUCTeX
ArabTeX
Beamer (LaTeX)
MiKTeX
PdfTeX