how to get a list of the connected wifi clients in OpenWrt 10.03?
You may use the arp-table, or DHCP-leases. Not a perfect solution, maybe it's enough?
... and combined
How about nmap?
Then do a stealth scan of your subnet (likely 192.168.1.0/24)
This will list services running on the clients as well. It may also set off alarms if the client has port-scan detecting software (i.e snort) installed so be careful.