I think that it is worth mid $$. Ok, the .org kills it a bit, but the other major extns are regged. The keyword is consistent with the TLD. Agree that dev potential is present and even a small effort might bring substantial rewards here.
The other thing worth noting is the singular esong.org
Frequency (MSN) 101000
Backlinks 7
Alexa Rank 735815
Traffic (Visits / Day) 350
(from estibot.com)
Some people might type in esongs.org in error. Get much traffic?
Good luck.
EDIT
Tried to validate the traffic at esong.org:
Traffic Rank Validation for: eSong.org
Sorry, Traffic Rank and daily traffic cannot be validated.
The domain eSong.org displays traffic rank that actually belongs to the domain inine.com.
Please disregard the traffic valuation and consider pure domain name valuation only.