Rest...Rest...Rest...and Rest,,, firstly rest, easy stretching of the calfs and lower legs, and possibly hams, increase the length, increase the strength,,,
Ice it and use ibuprofen gels while its swollen to get the swelling down, then apply heat/massage/etc when the sweling gone down, do cross training on the bike, but be careful still,, cycling is no impact but still involves pulling/pushing motions of the achilles,.
Use Glucosamine sulphate and Vitamin C to try and help the healing process, and see a physio/podiatrist, etc they are good guys here to help us and you may have a gait problem like me that has triggered the pain.
check this posting here::
http://www.runnersworld.co.uk/forum/forummessages.asp?URN=4&UTN=188&SP=324468708908328225208&V=6
for possibly more help