Gnokii works awesomely with the Nokia 5130c-2 (XpressMusic) model using the USB for communication.
/etc/gnokiirc configuration for getting it to work (took me some time to figure):
[global]
port = /dev/ttyACM0
model = 6510
initlength = default
connection = dku2libusb
use_locking = yes
serial_baudrate = 19200
smsc_timeout = 10
[xgnokii]
allow_breakage = 0
[gnokiid]
bindir = /usr/sbin/
[connect_script]
TELEPHONE = 09876543210
[disconnect_script]
[logging]
debug = off
rlpdebug = off
xdebug = off
A sample run
anacoluthon:~# gnokii --identify
GNOKII Version 0.6.26
IMEI : 012345678901234
Manufacturer : Nokia
Model : RM-495
Product name : RM-495
Revision : V 05.80
Send sms
anacoluthon:~# /usr/games/fortune | gnokii --sendsms +919936748748
GNOKII Version 0.6.26
Send succeeded!
Some gotchas:
Works as root only at the moment. Can’t get or set ringtones . SMS reader doesn’t work with xgnokii. The connecting USB cable is too short 
Next on the agenda, testing opensync with gnokii.