Help! configuring access-list

[ciscomeo]

My boss want's me to allow only http and smtp in and out in one of our routers. can any one assist me i how to configure an access-list?

The only understanding I have in an access-list are the following:

if i configure access-group in in e0 i am filtering packets going out
if i configure access-group out in e0 i am filtering packets going inside

For serial
if i configure access-group in in my serial 1 i am filtering packets going inside
if i configure access-group out in my serial 1 i am filtering packets inside going out

is my understanding correct? can any assist me on how I can implement the above request of my boss?

 

[Parcival21]

access-list 101 permit host <router address> any eq http access-list 101 permit host <router address> any eq snmp
on the interfaces
ip access-group 101 out
access-list 102 permit any host <router address> eq http access-list 102 permit any host <router address> eq snmp
on the interfaces
ip access-group 102 in

Hope I didn't mess something up,
bye,
busche