Metafilter, the 21st century's fountain of common knowledge and folk wisdom, has a thread full of good tips on getting new shoes to be comfortable. The advice focuses on leather shoes with a lot of DIY and purchase-alternative ideas. It seems that just about any household item, from soap to vodka, will soften shoe leather. However, there isn't much info on the damage that these "softeners" might do to your nice shoes. Highly recommended for anyone who walks in shoes!