If you mean translating IPX to TCP/IP I don't think you can do that since the protocols are so different.
What you can do is dual stack the network with both IPX and IP - so each device gets an IP and IPX address - and route both IPX and IP on your Catalyst 6500.
This will allow devices that still require IPX to use IPX within the LAN and use IP for internet access and everything else.
To configure IPX on a VLAN in the Catalyst 6500:
ipx routing
int vlan 30
description Network 1
ip address 192.168.100.1 255.255.255.0
ipx encapsulation ARPA
ipx network A53
