Here is a list of ports and what the port is used for.

echo= 7/tcp
systat= 11/tcp
chargen= 19/tcp
ftp-data= 21/tcp
ssh= 22/tcp
telnet= 23/tcp
smtp= 25/tcp
nameserver= 42/tcp
whois= 43/tcp
tacacs= 49/udp
dns-lookup= 53/udp
dns-zone= 53/tcp
oracle-sqlnet= 66/tcp
tftp= 69/udp
finger= 79/tcp
http= 80/tcp
alt. web port (http)= 81/tcp
Kerberos or alt web port (http)= 88/tcp
pop2= 109/tcp
pop3= 110/tcp
sunrpc= 111/tcp
sqlserv= 118/tcp
nntp= 119/tcp
ntrpc-or-dce= 135/tcp
netbios= 139/tcp
imap= 143/tcp
snmp= 161/udp
snmp-trap= 162/udp
bgp= 179/tcp
snmp-checkpoint= 256/tcp
ldap= 389/tcp
netware-ip= 396/tcp
timbuktu= 407/tcp
http/ssl= 443/tcp
ms-smb-alt.= 445/tcp/udp
ipsec (ike)= 500/udp
rlogin= 513/tcp
rwho= 513/udp
rshell= 514/tcp
syslog= 514/udp
printer= 515/tcp/udp
router= 520/udp
netware-ncp= 524/tcp
remotelypossible= 799/tcp
socks= 1080/tcp
bmc-patrol-db= 1313/tcp
notes= 1352/tcp
ms-sql= 1433/tcp
citrix= 1494/tcp
sybase-sql-anywhere= 1498/tcp
ingres-lock= 1524/tcp
oracle-srv= 1525/tcp
oracle-tli= 1527/tcp
pptp= 1723/tcp
winsock-proxy= 1745/tcp
remotely-anywhere= 2000/tcp
cisco-mgmt= 2001/tcp
nfs= 2049/tcp
compaq-web= 2301/tcp
openview= 2447/tcp
realsecure= 2998/tcp
ms-active-dir-global-catalog= 3268/tcp/udp
bmc-patrol-agant= 3300/tcp
ssql= 3351/tcp
ms-termserv= 3389/tcp
cisco-mgmt= 4001/tcp
nfs-lockd= 4045/tcp
pcanywhere= 5631/tcp
vnc= 5800/tcp
xwindows= 6000/tcp
cisco-mgmt= 6001/tcp
apc= 6549/tcp
irc= 6667/tcp
web= 8000/8001/8002/8080/tcp
cisco-xremote= 9001/tcp
netbus= 12345/tcp
quake= 26000/tcp
Bo= 31337/udp
rpc-solaris= 32771/tcp
snmp-solaris= 32780/udp
reackout= 43188/tcp
pcanywhere-def= 65301/tcp

for a complete list of ports check out
Book ref. for these ports can be found in Hacking exposed/ second adition also avaible on cd.