I did not used it myself, but it seems to have GUI on windows:
http://www.univ-provence.fr/gsite/Local/egee/dir/meglecz/QDD.html
Paper:
Meglécz, E., Costedoat, C., Dubut, V., Gilles, A., Malausa, T., Pech, N., Martin, J.F. 2010. QDD: a user-friendly program to select microsatellite markers and design primers from large sequencing projects. Bioinformatics 2010; Vol. 26,3 : 403-404; doi: 10.1093/bioinformatics/btp670.
Also you may try to search for "sputnik microsatellite". Sputnik was (is?) command based, but since it is very old (1994) a lot of ppl used it and cited. Some web servers may use it in combination with primer3. Still, do not count on a web server capable to take say 500Mbp genome and output all primers flanking microsatelites.