An earlier version of Ultimate Guitar allowed transfers to OnSong. This version apparently does not. I need to do this as my band uses OnSong.
I also found that the earlier version of ultimate guitar let me transfer songs directly into on song so I joined ultimate guitar paid a subscription fee and now I can't move the songs from ultimate guitar into on song directly. Actually I can't move the songs into onsong by any manner.
Does anybody have any suggestions?
I have the same question, since I'd like to use the base and drum parts of UG pro togheter with onsong. Suggestions much appreciated!
Not sure wether you can do this with Onsong, i use Newzik for that, works great for me, you just copy paste =)!
From an Onsong forum

www.ultimate-guitar.com has ended functionality with OnSong (and any other app that isn't devleloped by them). This issue is known by Jason Kichline (the creator/developer of OnSong) and is being reworked for the next release: v1.8 and should be out around the end of the month.

Since this unfortunate development, you can simply use Safari to visit www.ultimate-guitar.com and copy the chords or tabs that you are searching for (for FREE) and paste them into a new song: Songs>"+">New Song.
Since most of the songs I get from Ultimate Guitar need some editing work, my workflow is as follows.
  -  Identify the actual key of my target song
  -  Select the song and copy the text to memory
  -  Open text editor on PC.  (Make sure you use a fixed width font like Courier or Courier New) 
  -  Paste the copied text into text editor
  -  Make any adjustments, chord alignment etc.
  -  Save file to OnSong folder on Dropbox or other appropriate cloud storage facility
  -  Import into iPad from Dropbox
I use both UG/OS often and always re-work an arrangement to taste before uploading into Onsong.  My process is a little longer but the end result is exactly what I want.

1. Copy/past song into Open Office
2. Edit the layout or arrangement as needed in Courier font
3. Save as a plain text file to Dropbox
4. Upload into Onsong from Dropbox
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY