I'm trying to burn what appears to be about a 5.5GB ISO image using roxio. Before looking at the size of the file, I dropped in a DVD + R and quickly learned the size of my ISO image.

Any tips or tricks? Is there a way to burn this to two disks?

Do you have the ability to burn a dual layer DVD as this would be the answer.

Not sure, is there an easy way to check to see if my drive will support a dual layer burn?

There is file splitting software out there such as this one:

File Splitter, Large File Splitter, File Splitter Software - General File Splitter

Problem with splitting an ISO is that it's and image of a disc and not in parts. While this idea could be used for transporting the data, it would be useless for making any sense of the image.
Normally image burning software reconverts it to a usable format, such as DVD, which is then burnt.

The only other way around this would be to "mount" the image with an ISO imagining program such as PowerISO and extracting the data from there.

These can be quite daunting to use as they do require a certain amount of expertises.