I understand you cannot get married during the 6 days between Sukkot and Shemini Atzeret. I would like to get to married on 10/19/2003. This day is not within the 6 previously mentioned days. In fact shemini atzeret is over the 18th. However, simchat torah is the 19th. what is the ruling? simply, is the 19th ok or not?

You are right that during the days of Chol Hamo'ed it is forbidden to get married because one should not mix Simcha with Simcha meaning that one should not add another Simcha during Sukkot so as not to lessen the Simcha of Sukkot. Regarding your question, in the case you will be married in Eretz Yisrael than there is no problem with getting married on the ninteenth, on the other hand if the wedding will take place in Chutz La'aretz - not in Israel, than the ninteenth is Yom Tov - Simchat Torah, and it is forbidden to be wed on Yom tov. Mazal Tov and Kol Tuv. Rabbi Yosef Weitzen