Hi,
Unfortunately there is not a trial version of the Modulation Toolkit available. Typically if you want to "test drive" a LabVIEW toolkit or addon, you can do so by going to the online evaluation found here:
Try LabVIEW Add-Ons FREE OnlineHowever, I discovered that the online evaluation does not have the Modulation Toolkit installed. I have made the necessary parties aware of this, and we intend to have this added soon (so thanks for bringing it to my attention!

).
In the meantime, I would recommend checking out the
Baseband Developer's Kit. All you have to do is download and install the executable. You won't get the full look and feel of the toolkit, but you will get a general idea of some of the waveforms that you can create and analysis that you can do.
Regards,
Andrew W
National Instruments