What software are you looking for ?
We are an Authorized Reseller of Google Apps. GApps gives you distinct advantage by bringing down the cost for emailing solution. With GApps you do not need any hardware or software at your premises. You get 25 GB of inbox space for each user in your organization. Besides email you also get Apps like Calendar, Document collaboration, Websites, Instant Messaging using GTalk, Video site for your domain.
Other - TinyOS