I mentioned earlier the ways that the data can be imported from your old Sidekick from TMobile's webpage to the new Sidekick 4G.
Before transferring your service, place the SD card currently in the SK 4G into the old Sidekick and save your photos onto it. Next is download the utility to send your other info to the SIM card, and do the transfer. I didn't do it this way, but it could easily be a headache-free way to transfer your data.
What I did was a bit different since I was told to use synchronize when importing my data but it never worked for some reason. TMobile's site has a page called MobileLife. Go there and follow the prompts to upload the CSV or VCF file and then click synchronize. You may need to compare what's on the old SK with the info on the website. Then update and synchronize every now and then. If you transferred the pics as transferred above and put it back into the new SK, you're in good shape.
Next was a little troublesome for me for some reason. Use the USB cable to transfer your Notes from your export from the computer to the new Sidekick. You'll see a menu of choices, one of them is to use the SK as a mass storage device. Choose that. Your computer should detect the SK and set up a drive in My Computer for you to make the transfer. Then copy the files from the export directory onto that drive. In my case, it set up the SK as drive E:.
Some of you may have used Intellisync to do the transfers. Customer Service may be able to help if all else fails. I did a bit of research on this as well before doing my transfers.