Need some help.

A friend of mine told me that I could have an old lens of his for free because he was no longer interested in photography. He said that he had had it for some time, but that it was still in good condition. He could not remember what brand it was. My question is, do they make converters to allow me to use a different company's lens on my 30D. It would be really nice because he said that it is a 400mm lens! Sure would save me a lot of money. If anyone could point me in the right direction I would really appreciate it. Thanks.

Depends on the lens, but many can be used with a converter. Some, especially older Leica and Zeiss are as good or better than what is available today. Others, like the Canon FD mount, require converters with lenses that are 1) quite pricey and 2) generally suck. Can you find out the brand of lens and the mount?

As Roger said, it may be possible but if you do get it attached it will be manual focus only.