My company is the registered owner of a class C block, and we
currently use Sprint as our provider.  We want to put in PTR records
for a number of reasons, but Sprint is unable to simply add them. 
Their DNS department has also been unable to tell us what we should do
besides a generic "contact ARIN".

Can anyone provide assistance or a pointer/reference to what should be
done to allow PTR records for our own netblock?

Thanks in advance,

Scary

(The following assumes that you are in North America and hence under
the authority of ARIN.)

If you have a network allocation directly from ARIN, you will need to
submit a completed Network Modification template
(http://arin.net/library/templates/netmod.txt) to hostmaster@arin.net.
 Fields 5a and 5b allow you to specify name servers to use for
in-addr.arpa delegation.  You would want to specify your own name
servers there and ensure that you are publishing PTR records for the
appropriate addresses.

However, it is more likely that your space is being reassigned or
reallocated to you by Sprint.  In this case, you will need cooperation
from Sprint, not ARIN (as Sprint has more than /16 of space, and has
therefore been delegated the entire /16 in-addr.arpa zone).  I have
used the form at http://sprint.net/maint/dns_template.cgi in the past
to request that Sprint delegate the appropriate /24 in-addr.arpa zones
to my name servers.  According to the DNS Policy linked at the top of
that template, Sprint is also willing to host your PTR records on
their DNS servers.

I hope this helps.

Thank you. It is a direct allocation (we were early).  I did that, and
I have the templates I think I need to get it straightened out.  It is
a mess though.
I think i have to assing my id to the org first, then request changes.
 Not looking forward to it.

Would you be willing to fill out the templates on our behalf if we
provided the information necessary?  As a separate fee/question of
course.

Thanks for your assistance; feel free to repost as an answer vs. a comment.

Scary

Scaryberry,

Derat-ga is not a Google Answers Researcher, and thus cannot post an
offical answer nor receive compensation. One very interesting thing
about Google Answers is that useful information is sometimes posted
free of charge by helpful commenters.

To tell a Researcher from a non-Researcher, look at the username. Only
Google Answers Researchers' usernames are clickable hyperlinks.
Clicking on such a link will take you to the Researcher's answer
profile, where you can view ratings information and read previous
answers which that Researcher has posted.

Pinkfreud, you are truly omnipresent.  In my rush to thank derat, i
forgot to notice they were not a Researcher.

Well Derat, a tip of the hat to you.  If no one else posts an answer,
I'll submit the fee and tip to the charity of your choosing.

Thanks again (and to you, Pinkfreud),

Scary