I have a shower, but since i just started commuting, the weather is cool, and my commute is only 10 miles... i haven't used it. I just chill out for a few minutes after I get to work to let my body cool down and then when i change i towel off real quick, wash face and hands, throw on some deoderant, just a touch of cologne and I'm good to go. No problems so far.
I think cooling down before doing anything is what really helps. This way i'm not sweating on my clean clothes after i change. I also make sure i get to work earlier than normal to make up for any lost time doing this.