First, great job putting something like this together! I was definitely looking for a way to transfer my 1000+ SMS messages from my old E61 to my N900. After using the tool I have a couple of observations:

• The instructions mention exporting the SMS messages as a CSV. Upon inspecting the code, I realized that the program is expecting a semicolon ( ; ) as the delimiter. Just as a heads up to people who might be trying this out with a true CSV file (delimited by commas), you'll get a Segmentation Fault. Use semicolon delimiters instead.
• After I ran the program, I checked the Conversations app to make sure the messages had been imported. They had, of course. The only weird thing is that, despite having the correct dates from when I sent/received them, they showed up at the top of the Conversations list, despite being much older than messages I sent on the N900 recently. I rebooted the device, but that didn't change anything. This is only an issue for those like me who have already been using the N900 prior to running this import. Not a huge deal, but slightly annoying.

In any case, if you take the above into consideration, this is a great tool for those migrating from other devices and who want to retain their SMS communication history.