I know that this is likely to be the least technical SSIS blog entry you read today, but it's still useful, and no one else I've talked to seems to know that you can do it, so I'm going to blog on it anyway.
If you hold down the ctrl key on your keyboard and scroll the wheel on your mouse, you can zoom in and out of your SSIS control flow or data flow designer in Visual Studio. This is really handy for those extra-large packages when you need to see more than your monitors permit, and since the built-in designer tools have inconsistent support for zooming in control flow and data flow, it's both convenient and consistent.
Low tech, but cool and useful.
And to make this even more useful, you can use the same technique in just about any modern Windows application that supports zooming, including Internet Explorer and Word. Enjoy!