Warp has been much improved since its initial release. Definitely worth reinstalling if you haven't used it in a while.

You can grab windows, apps, files and warp them along to another space with no problem. Its also got this neat little preview thing if you turn on the "Click screen edge to warp".

One little problem for people using AppFresh: There's another app (a screensaver) called Warp, which Appfresh recognizes, so you have to change the Iusethis identifier in AppFresh if you want to get it right.

Just updated to Leopard yesterday, and Spaces is definitely one of the best new features... this app here makes it even better, it is so convenient to drag windows to another space just by dragging them on the edge of the screen... a lot more intuitive than launching spaces, and drag them around in miniature size.
So far it works perfectly! Really good job!

Yea, nontroppo is correct... you just move your mouse to the edge of the screen and it transitions to the next Space. Normally this would suck, but they have an option to set a short delay before it transitions. I'm using Warp constantly.

I assume you move to the side the desktop you wish to get to is and it will autoswitch. This is different to the spaces trigger in OSX which shows all spaces and you click one to get there.

Sorry, how does this differ from the current Apple set up?
Being able to use the mouse to access spaces is customisable already through use of middle/right button, or assigning it to an expose hot corner, on top of a myriad key combinations.