"Locked" USB dongle modems are another rip off by the cell phone industry. With a bit of ingenuity you can unlock a locked modem, but it can involve re-flashing the firmware which is not for the faint hearted.
I recently acquired an ASUS T500 3.5G PC Card (cost was somewhat less than $150) and it is non-network specific. This is a PC Express Card, but it comes with an adapter into which it plugs, with a double USB lead, one for signal and power, and the other just for power (I actually manage to use it with just one USB lead - Power & Signal plugged in - but depending on your Netbook - you may need to use both leads - ie. use two USB ports on your Netbook).
It comes with software on a CD-ROM (350Mb) - if you don't have an external CD-ROM drive for your Netbook you can copy it to a memory stick and install from there.
When you have installed the software on the Netbook, and inserted your SIM card into the T500, it recognises who issued the SIM card and automatically sets itself up for that ISP.
There are 3G devices that look like a fat memory stick (and only use one USB port). Sony Ericsson make one, as do Huawei (the E169G). I haven't tried one - but I'm interested ...
I would strongly suggest that you only use a pay-as-you-go SIM card for data (you load it with some airtime and then "buy" a databundle from your airtime. Only load just over the amount you need for the databundle - reason being that once you exceed the databundle that you have loaded, the "out-of-bundle" rate jumps by a factor ten (or more) and starts really depleting the balance of your airtime.
You don't specifically need a 3G SIM card - my experience is that any 32K SIM card will work fine. I buy 'em from a Discount Pharmacy at about $0.10 each - you may need to put them into a phone to activate them and load the databundle. You may need more thasn one SIM card because some SP's make it very difficult to recharge them within the thirty day validity of the initial bundle - and some require you to make at least one call, or send one text to keep them valid.
BE VERY CAREFUL of combined voice/data SIM cards - I had a very expensive experience earlier in the year when I exceeded my databundle and wound up with a $10 000 bill at the end of the month Mobile Service Providers sure know how to milk their customers - barstewards! Also, when using a mobile handheld as a modem, you can't use it as a phone ...
Am now running the entire household off pre-paid SIMs - no more nasty shocks at the end of the month!
Need any more info or help - just post to the forum...
Last edited by Feline; 2nd Feb 2009 at 11:50.
Reason: left a word out - Doh!