The colors of yellow/white are used in the church until Pentecost Sunday, when we have red. (We love red here at the SKC Observer syndicate.) Depending on which faith tradition you are following you can have red again the next Sunday or go back to the gold/white of Eastertide. Then it's the green of ordinary time until October/November.
So for this year, Pentecost Sunday is June 12, 2011.
Ordinary time then sets in, starting Sunday, June 26th and running clear to the beginning of Advent, the first Sunday of which is November 27th. You can do something for All Saints Day around November 1 if you want.