I was recently contacted by Moshe Wagner who wanted to know if there was a graphical front end to the Zmanim API. While there are various programs that do use the API, there is no standalone Java GUI that uses the API (the zmanim clock applet is not easily useful for looking up zmanim for various locations). As first announced in Hebrew (ZmanimGUI – ממשק להצגת זמני היום ההלכתיים), Moshe took the API and wrote a Java Swing GUI for the API. The Zmanim GUI (called זמני היום in Hebrew) can switch between Hebrew and English display and shows the most common list of zmanim typically used. The program requires Java 6 and can be launched by double clicking on the ZmaniGui jar file (or execute the command ‘java -jar ZmaninGui.jar’ from a command prompt). As with the Zmanim API, the GUI was released under the GPL2 and is available (including source) on our download page (direct link to version 0.0.87 updated on י״ח אייר תשס״ט May 12, 2009). Questions and comments can be posted here or sent directly to Moshe at moshe.wagner -AT- gmail.com.
how do you check the zemanim?
I am not sure exactly what you are looking for, but does the KosherJava Zmanim Map provide the zmanim you are looking for? This GUI requires a JVM to run and you may find the map simpler to use.