Since file syncing is what all the kids are into these days, I thought I'd do a rundown on all the choices we PowerPC users have. It's not just Dropbox, right? There must be more...
Well, for Leopard users, yes. There's SugarSync, SpiderOak, and Wuala in addition to Dropbox (a couple of others, Minus and Mozy Stash, say they support Leopard but are Intel only). However, for Tiger users, there's only Wuala. I'll write more about Wuala and Dropbox below since I've tested them on Tiger, but since I don't have Leopard here's a quick feature breakdown of the other services:
SugarSync starts off with 5 GB free storage and has pricing plans for 30, 60, 100, 250, and 500 GB. The main difference with DropBox is you can sync any folder, no need for symlinks. It also supports music playback and public links. However, there doesn't appear to be any LAN syncing, and the consensus is that the desktop client uses more system resources.
SpiderOak is all about security as your password is stored locally on your computer. No one at SpiderOak knows it, so they haven't suffered from embarrassing security snafus like Dropbox has. They offer 2 GB free storage, plus $10 a month for each 100 GB increment thereafter. Like SugarSync, you can sync any folder, and it also lets you back up external/thumb drives.
And now for the Tiger clients:
Wuala is much like SpiderOak in that the client stores your password locally so not even Wuala employees can access your account. Security and privacy are paramount. They offer 5 GB free storage plus 20, 50, and 100 GB paid plans.
It's a testament to how the onset of "apps" have made us feel dumb by how a client with a little complexity like Wuala makes me feel, well, dumb. It's not the super simple client like Dropbox, but it offers more flexibility. You can choose any folders to either backup or sync, and the client works basically like another Finder window. It's a bit of a learning curve, but after a few minutes you get the hang of it. One downside, the web interface requires the java plugin, which if you care about security, you may want to avoid. Also, the desktop client uses a bit more system resources than Dropbox.
Finally we have Dropbox, which due to its simplicity, many users new to syncing may want to use for its... simplicity. Signup and usage are as easy as it gets. They offer 2 GB free storage, plus paid plans of 50 and 100 GB (with some bonuses for referrals). All you do is drop the files/folders you want to sync in your Dropbox folder and it takes care of the rest fairly quietly in the background. It's not as flexible as the others as to which folders you choose to sync, but they have a nice web interface. There they make it much easier to get sharing links than in Wuala. Also, a big plus is syncing over a LAN network. So if you want ease of use and performance over flexibility and security, Dropbox is your best bet.
And if you're just looking for simple online backup without syncing, Mozy has a good desktop client with regularly scheduled backups of specified files and folders. Though their new syncing client Mozy Stash is Intel only, as noted above.
One last thing, I added another link to the sidebar for My Mac Collection. There's a lot of good stuff there the last few days, so check them out!