I had previously reported using wvdial for ubuntu 9.10;

I have the MF636 Telecom XT stick working well in Ubuntu 10.04 beta using the standard network manager;

steps:
1) "flip" device's ID so linux sees it as modem
2) configure
3) connect

1) .. flip modem by ..... opening terminal and pasting in the text in italics
step a) sudo gedit /etc/udev/rules.d/zte_eject.rules
that loads the programme gedit then paste into gedit (text editor) that opens the text in italics
step b) SYSFS{idVendor}=="19d2", SYSFS{idProduct}=="2000", RUN+="/usr/bin/eject %k", OPTIONS+="last_rule" 
step c) save and close gedit (I put commands in italics as I can't find a quotation button!)

2) configure by right-clicking network manager; select mobile broadband; then country and network

3) left click on network manager; click on Telecom option displayed; should connect < 5 secs