Some folks over on the OmniWeb mailing list were wanting the Omni folks to add a feature to open the current OmniWeb URL in that other browser. Anyway, there’s no need to disturb OW, just add the following script to ScriptMenu.
on run
tell application "OmniWeb"
set insertURL to address of browser 1
end tell
tell application "Internet Explorer"
GetURL insertURL
end tell
end run