As the 3.5mm connect becomes more and more common, on iPods, laptops etc. the need to convert to other, bigger professional style connectors is almost a daily one for those of us working with audio.
Here's a good quality .5M adaptor lead. The essential for everyone's toolbox. Suitable for connecting to standard mic leads and audio snakes. See also the mini 3.5mm jack to XLR male adaptor on this page of our site.