There is a new beta of PasteBinIt available with a nice feature: highlighting support. This means that you can click in the line number gutter of the code view to set a marker that will show up in the pastebin as a yellow marked line
In addition some UI tweaks have been made such as listing the 5 most recent syntax highlightings at the top of the menu.
Get the update here or use the integrated updater if you have already downloaded version 0.2–2.