SafariSort is a Universal application and has been successfully tested on Lion Snow Leopard and Leopard. It "should" work on Tiger. The SafariSort download is hosted on MacUpdate. 
SafariSort - Get Sorted
The Missing Safari Option
I find it frustratingly ridiculous that Apple does not provide the ability to alphabetically sort Safari bookmarks. Apple recently released it's fifth version of Safari; sorting bookmarks is still not an option.
I actually like Safari; it's a decent browser. Safari's OS X integration makes it my primary browser. I used to export my bookmarks to Firefox just to sort them. What a pain in the ...
Time to Get Alphabetical
SafariSort will alphabetically sort your Safari bookmarks in just one click! All your folders, sub-folders and bookmarks will be sorted enabling you to actually find what you're looking for. Simply Amazing!
PS. It's FREE, Happy Sorting!