Yes it is possible
You must configure a logical channel interface on the switch
Cat3550(config)#int port-channel 1
Cat3550(config-if)#exit
than assign ports to channel
Cat3550(config)#int fa0/2
Cat3550(config-if)#channel-group 1 mode on
Cat3550(config-if)#exit
Cat3550(config)#int fa0/3
Cat3550(config-if)#channel-group 1 mode on
Cat3550(config-if)#exit
If you need trunk between devices--->
Cat3550(config)#int port-channel 1
Cat3550(config-if)#switchport mode trunk
Router
Create a logical channel interface to form an EtherChannel.
Cisco7200(config)#int port-channel 1
Cisco7200(config-if)#exit
and f.e. ports fa3/0 and fa4/0 are configured as members of the logical channel to form an EtherChannel group
Cisco7200(config)#int fa3/0
Cisco7200(config-if)#channel-group 1
Cisco7200(config)#int fa4/0
Cisco7200(config-if)#channel-group 1
For trunk
Cisco7200(config)#int port-channel 1.10
Cisco7200(config-subif)#encapsulation dot1Q
Cisco7200(config-subif)#ip address 10.10.10.1 255.255.255.0
Cisco7200(config-subif)#exit
Cisco7200(config)#int port-channel 1.20
Cisco7200(config-subif)#encapsulation dot1Q
Cisco7200(config-subif)#ip address 10.10.11.1 255.255.255.0
Cisco7200(config-subif)#exit
Cisco7200(config)#exit
Cisco7200#
HTH
m.sir
