Depending on how many new admits you do per month you may consider out sourcing your billing. If you do that then you can use the HAVEN Data Entry Software provided by CMS for free for transmission of OASIS data.
http://www.cms.hhs.gov/oasis/havensof.asp
I have used Healthcare Assitant by Synergy for about 4-6 months and I really like the interface.
http://www.2synergy.com
It can submit your OASIS, perform billing functions, print 485, and much more. Synergy has on staff billers that can actually bill for you (or answer questions) if you need help or fill in due to one of your billers being sick, vacation, etc.
Whatever software you decide to use, be sure to demo it and find out all the fees.
SafeTman