Common Port Assignments are:

7 Echo

19 Chargen

20-21 FTP

22 SSH/SCP

23 Telnet

25 SMTP

42 WINS Replication

43 WHOIS

49 TACACS

53 DNS

67-68 DHCP/BOOTP

69 TFTP

70 Gopher

79 Finger

80 HTTP

88 Kerberos

102 MS Exchange

110 POP3

113 Ident

119 NNTP (Usenet)

123 NTP

135 Microsoft RPC

137-139 NetBIOS

143 IMAP4

161-162 SNMP

177 XDMCP

179 BGP

201 AppleTalk

264 BGMP

318 TSP

381-383 HP Openview

389 LDAP

411-412 Direct Connect

443 HTTP over SSL

445 Microsoft DS

464 Kerberos

465 SMTP over SSL

497 Retrospect

500 ISAKMP

512 rexec

513 rlogin

514 syslog

515 LPD/LPR

520 RIP

521 RIPng (IPv6)

540 UUCP

554 RTSP

546-547 DHCPv6

560 rmonitor

563 NNTP over SSL

587 SMTP

591 FileMaker

593 Microsoft DCOM

631 Internet Printing

636 LDAP over SSL

639 MSDP (PIM)

646 LDP (MPLS)

691 MS Exchange

860 iSCSI

873 rsync

902 VMware Server

989-990 FTP over SSL

993 IMAP4 over SSL

995 POP3 over SSL

1025 Microsoft RPC

1026-1029 Windows Messenger

1080 SOCKS Proxy

1080 MyDoom

1194 OpenVPN

1214 Kazaa

1241 Nessus

1311 Dell OpenManage

1337 WASTE

1433-1434 Microsoft SQL

1512 WINS

1589 Cisco VQP

1701 L2TP

1723 MS PPTP

1725 Steam

1741 CiscoWorks 2000

1755 MS Media Server

1812-1813 RADIUS

1863 MSN

1985 Cisco HSRP

2000 Cisco SCCP

2002 Cisco ACS

2049 NFS

2082-2083 cPanel

2100 Oracle XDB

2222 DirectAdmin

2302 Halo

2483-2484 Oracle DB

2745 Bagle.H

2967 Symantec AV

3050 Interbase DB

3074 XBOX Live

3124 HTTP Proxy

3127 MyDoom

3128 HTTP Proxy

3222 GLBP

3260 iSCSI Target

3306 MySQL

3389 Terminal Server

3689 iTunes

3690 Subversion

3724 World of Warcraft

3784-3785 Ventrilo

4333 mSQL

4444 Blaster

4664 Google Desktop

4672 eMule

4899 Radmin

5000 UPnP

5001 Slingbox

5001 iperf

5004-5005 RTP

5050 Yahoo! Messenger

5060 SIP

5190 AIM/ICQ

5222-5223 XMPP/Jabber

5432 PostgreSQL

5500 VNC Server

5554 Sasser

5631-5632 pcAnywhere

5800 VNC over HTTP

5900+ VNC Server

6000-6001 X11

6112 Battle.net

6129 DameWare

6257 WinMX

6346-6347 Gnutella

6500 GameSpy Arcade

6566 SANE

6588 AnalogX

6665-6669 IRC

6679/6697 IRC over SSL

6699 Napster

6881-6999 BitTorrent

6891-6901 Windows Live

6970 Quicktime

7212 GhostSurf

7648-7649 CU-SeeMe

8000 Internet Radio

8080 HTTP Proxy

8086-8087 Kaspersky AV

8118 Privoxy

8200 VMware Server

8500 Adobe ColdFusion

8767 TeamSpeak

8866 Bagle.B

9100 HP JetDirect

9101-9103 Bacula

9119 MXit

9800 WebDAV

9898 Dabber

9988 Rbot/Spybot

9999 Urchin

10000 Webmin

10000 BackupExec

10113-10116 NetIQ

11371 OpenPGP

12035-12036 Second Life

12345 NetBus

13720-13721 NetBackup

14567 Battlefield

15118 Dipnet/Oddbob

19226 AdminSecure

19638 Ensim

20000 Usermin

24800 Synergy

25999 Xfire

27015 Half-Life

27374 Sub7

28960 Call of Duty

31337 Back Orifice

33434+ traceroute