Most male yeast infections are easily treated with an over-the-counter antifungal treatment, such as Monistat (yes, men can use it too). Apply the medication directly to the affected skin twice daily for a week. If the rash doesn't go away, or if it recurs frequently, consult your doctor.
Probiotics are a popular natural remedy for yeast infection. The type of probiotic being studied for yeast infections is Lactobacillus, especially Lactobacillus acidophilus (which is also present in yogurt)