One of the first applications you should load on mobile devices is some type of backup utility so that all your vital data is not lost when you are out on the road. Sprite Backup has always been my personal favorite for Windows Mobile devices due to the advanced backup options and reliability with restoring from a reset. Another excellent feature of Sprite Backup is the ability to restore after a ROM update. Sprite Software announced the release of Sprite Backup 5.1 for Windows Mobile 5.0 Smartphones so they now have you covered for Pocket PC and Smartphone devices. For enterprise customers peace of mind, backups can be encrypted so if a device is lost then the data remains secure in the backup. They are still working on Motorola Q and Orange Smartphones. Sprite Backup is available for US$29.95.
If you have a device running the Palm OS, then I personally highly recommend Resco Backup. I have tested many Palm backup solutions and I find Resco Backup to give me the fastest, most complete, and reliable backups. The application also supports encrypted backups and individual file backups to keep your data safe. Resco Backup also only costs US$14.95.
Sprite Software also has a backup solution for S60 devices although I have to admit I just found this out when creating the blog entry and haven't yet tried it myself. I also need to admit that I have been spoiled by the rock solid performance with my latest S60 devices and have not backed any of them up yet. If you know of a good backup solution for the S60 platform, feel free to share it here for others to try.