Licensed under the same terms as Perl:
http://perldoc.perl.org/perlartistic.html
http://perldoc.perl.org/perlgpl.html

Some parts of this software distribution are derived from the APNIC,
LACNIC, ARIN, AFRINIC and RIPE databases (copyright details below).
I am not a lawyer, so please direct questions about the RIR's 
licenses to them, not me.

APNIC conditions of use

The files are freely available for download and use on the condition 
that APNIC will not be held responsible for any loss or damage 
arising from the application of the information contained in these 
reports.

APNIC endeavours to the best of its ability to ensure the accuracy 
of these reports; however, APNIC makes no guarantee in this regard.

In particular, it should be noted that these reports seek to 
indicate the country where resources were first allocated or 
assigned. It is not intended that these reports be considered 
as an authoritative statement of the location in which any specific 
resource may currently be in use.

ARIN database copyright

Copyright (c) American Registry for Internet Numbers. All rights reserved.

The ARIN WHOIS data is for Internet operational or technical research
purposes pertaining to Internet operations only.  It may not be used for
advertising, direct marketing, marketing research, or similar purposes.
Use of the ARIN WHOIS data for these activities is explicitly forbidden.
ARIN requests to be notified of any such activities or suspicions thereof.

RIPE database copyright

The information in the RIPE Database is available to the public 
for agreed Internet operation purposes, but is under copyright.
The copyright statement is:

"Except for agreed Internet operational purposes, no part of this 
publication may be reproduced, stored in a retrieval system, or transmitted, 
in any form or by any means, electronic, mechanical, recording, or otherwise, without prior permission of the RIPE NCC on behalf of the 
copyright holders. Any use of this material to target advertising 
or similar activities is explicitly forbidden and may be prosecuted. 
The RIPE NCC requests to be notified of any such activities or 
suspicions thereof."

LACNIC database copyright

Copyright (c) Latin American and Caribbean IP address Regional Registry. All rig
hts reserved.

AFRINIC copyright

Seems to be the RIPE copyright. I'm sure they'll correct this in due course.