Like many developers, I too think I have a unique compression algorithm... but I know there are at least 6 million algorithms out there and (6 million - 1) of these are patented... it is highly probable that somebody has thought of this already. I'd like to find out.
Ideally, somebody could show me a page where I would have a 10,000 foot view of most of the known compression techniques. This a brief description of how each works and the pros and cons of each.
I would recommend the comp.compression FAQ. Even if it hasn't been updated since 1999, it is still a good starting place. It also contains information that will help you make sure you actually have a workable compression idea (I hate to bear bad news, but it is awfully easy to think you have created a flawless new compression algorithm, and not see how frequently and by how much the algorithm expands rather than compresses. If you haven't done it yet, you should look at your method and figure out what your "worst case" is -- if the worst case isn't bad enough, it may be a clue that the method doesn't actually compress losslessly after all.)
Might I suggests Google Patents?
If you know the exact technical terms you should be able to search for a number of compression algorithms. It is much cheaper than paying an attorney to do a patent search.
If you find a patent that is similar to your idea, check what is called the "forward references" - or in layman's terms, a list of patents based on the one you are looking at. Your compression algorithm might be unique, even if you find a patent that is close, especially if it improves upon it in some (usually unforeseen) way.
As always, when in doubt, ask a patent lawyer! If your idea is good enough, it will be worth the money to approach them about it.