Yes, it's an interesting topic. Someone emailed me a while ago
asking if it was possible for an amateur to receive pulsar signals
and so I did some looking into the whole subject. Here's a bunch
of papers I found and read...

Two Allan deviation graphs attached, taken from:

Relativity and Timing in X-ray Pulsar Navigation
-- N. Ashby and D.A. Howe 
http://tf.nist.gov/timefreq/general/pdf/2166.pdf


Then there's this old paper, by Allan himself:

Millisecond Pulsar Rivals Best Atomic Clock Stability 
-- D.W. Allan 
http://tf.nist.gov/timefreq/general/pdf/751.pdf


And for extreme details on reception and corrections:

Chapter 8 High-Precision Baseband Timing of 15 Millisecond Pulsars
-- Aidan Wade Hotan
http://adt.lib.swin.edu.au/uploads/approved/adt-VSWT20060822.151026/public/10chapter8.pdf
http://adt.lib.swin.edu.au/uploads/approved/adt-VSWT20060822.151026/public/

Binary and Millisecond Pulsars at the New Millennium
-- Duncan R. Lorimer 
http://relativity.livingreviews.org/Articles/lrr-2005-7/
http://relativity.livingreviews.org/Articles/lrr-2001-5/download/lrr-2001-5Color.pdf


Some other interesting pulsar timing papers:

Millisecond Pulsar Observation System At CRL
-- Y. Hanado,H. Kiuchi, S. Hama, A. Kaneko, and M. Imae
http://tycho.usno.navy.mil/ptti/1991/Vol%2023_34.pdf

Millisecond Pulsar Observation at CRL
-- Y. Hanado, M. Imae, M. Hosokawa, M. Sekido, A. Kaneko, and Y. Shibuya
http://tycho.usno.navy.mil/ptti/1998/Vol%2030_08.pdf

An Ensemble Pulsar Time
-- G. Petit, C. Thomas, and P. Tavella
http://tycho.usno.navy.mil/ptti/1992/Vol%2024_09.pdf

Limits to the Stability of Pulsar Time
-- G. Petit
http://tycho.usno.navy.mil/ptti/1995/Vol%2027_30.pdf 

Application of Millisecond Pulsar Timing to the Long-Term Stability of Clock Ensembles
-- R. S. Foster and D. N. Matsakis
http://tycho.usno.navy.mil/ptti/1995/Vol%2027_36.pdf

Pulsar-Appropriate Clock Statistics;
-- D. N. Matsakis and F. J. Josties  text 
http://tycho.usno.navy.mil/ptti/1996/Vol%2028_19.pdf

Spacecraft Navigation Using X-ray Pulsars
-- Suneel I. Sheikh, Demetrios Matsakis
http://tycho.usno.navy.mil/IAU31/sheikh.pdf

Long-term Timing at Arecibo and Green Bank
-- Ingrid Stairs
http://tycho.usno.navy.mil/IAU31/stairs.pdf

Pulsar Clock
-- D.W. Allan and G.M.R. Winkler 
http://tf.nist.gov/timefreq/general/pdf/661.pdf

PTTI Index of papers:
http://tycho.usno.navy.mil/ptti/index9.html

Enjoy,

/tvb