Synchronisation across multiple computers using the Import and Export tools.
When you make updates on one computer which you would like transferred to another one, simply export your user file to a some removable device (floppy disk, CD-R, email etc). Then on the second computer open up your current file and select File->Import. Select the file which you exported to on the other computer and click Open. All sites that exist in the file you are importing from but not in the file you are importing will be added. For every site which already exists you will be prompted to overwrite the current one with the imported one. You are able to select Yes to All to overwrite all without asking and No to All not to overwrite any. Select No to All if you only want new sites to be merged with the current file. If you made changes to existing sites on the first computer, then Yes to All is probably your best choice to get all of the changes into the second computer (note: If you select Yes to All changes you made on the second computer may be overwritten).
After an import, you will need to save the file for the changes to become permanent. If something goes wrong in the importing process simply exit without saving.