I wrote a simple ruby script to help with loading large lists of URLS/IP's into Burp Proxy. Historically, I would just use the "Open Multiple Tabs" add-on in Firefox to accomplish the task, but when confronted with an external pentest for 300+ vhost's I decided it was time for a change. The best part is bypassing the SSL certificate check.
I have to assume there are other tools out there that do something similar, but this works for me. I'd rather code my own tools anyway.
./burp_loader -f filename
-f, --file FILENAME A line separated file of targets
-q, --quiet Disable verbose messages
-h, --help Display this screen