Using Debian Etch this is how I sync'd my Nokia 6230's phonebook, messages, misc.

Plug USB IrDA into PC

This is what dmesg reports when I plug in mine:
SigmaTel STIr4200 IRDA/USB found at address 3, Vendor: 66f, Product: 4200
drivers/net/irda/stir4200.c: IrDA: Registered SigmaTel device irda0
usbcore: registered new driver stir4200

Install irda-utils package:
apt-get install irda-utils

You will be prompted to configure the setup. Here is what I selected:
Enable IrDA on system startup: Yes
Discovery behavior: Yes
IrDA device type: native
FIR chip type: stir4200
Module options for the FIR chip: I left it blank
Port for setserial to quiet: I left it blank

This will automatically load the kernel modules 'irda' and 'stir4200'. Now you must load the drivers 'ircomm' and 'ircomm-tty'. Now use your program of choice. The device to use should be /dev/ircomm0. I have used Wammu and Kmobiletools.