Primer 3 is still the best. You can download and install it locally (sourceforge.net/projects/primer3) or use a web-based interface available at numerous sites.
MISA is a very useful package for microsatellite search as well for automated primer design using the Primer 3 model:
You can use websat tool where u can identify the SSR regions in sequence(s) and also get the primers (STMS) for those identified SSR s with the help of Primer 3 module which is already present in Websat.