Few things are more annoying than software that doesn't deliver the goods -- especially when your business is paying for the privilege of being annoyed. But no matter which application is driving you nuts these days, there is probably an open-source alternative availableHere are a few of the chief contenders for the "World's Most Annoying Software" title, along with some worthy open-source alternatives. While these products vary in their quality and functionality, and while none of them will satisfy every small-business owner enough to justify making a switch, they are at least worth a closer look.

Adobe Acrobat. If you're an enterprise document-management specialist, there is probably no software package on earth that replace Acrobat. If you're a typical small-business owner, however, "bloat" doesn't begin to describe what has happened to Acrobat's feature set (and its code base) over the years. While there are a number of small, fast, reliable, free tools that deliver a subset of Acrobat's feature set, I suggest making PDFCreator your first stop if you're hunting for a suitable alternative.

Microsoft Project. I am actually a bigger fan of Project than I am of most Microsoft business-productivity applications. Project does, however, take a chunk out of your pocketbook -- and like Microsoft Office, many smaller companies only need a subset of its full feature set. If you would like to check out an open-source alternative that compares quite favorably to Microsoft Project (that is, in everything except price), give Open Workbench a try.

Adobe Dreamweaver. Here, too, the main problem with Dreamweaver isn't its quality; it's the fact that you'll pay through the nose for a Web publishing tool that gives many users far more power and functionality than they actually need. If you're looking for a reliable, no-cost alternative that will give many small businesses everything they need to build and maintain a Web site, consider NVU, which is available for both Windows and desktop Linux users.

Intuit Quickbooks. I'm a bit reluctant to suggest an alternative to Quickbooks, since I am no expert in accounting software by any stretch of the imagination -- and replacing an application like this definitely takes a small business into territory where many rightly fear to tread. When I ask around about this issue, however, I hear a lot of good things about Compiere, which comes in both completely free and premium (but still reasonably priced) editions. Compiere is also making a name for itself as a viable alternative to proprietary CRM and ERP applications, especially among smaller companies that could benefit from these tools but can't afford either the up-front licensing costs or the ongoing service and support expenses they'll pay for proprietary products.

AOL Instant Messenger. Actually, it doesn't matter whether you and your employees use AIM, MSN Messenger, Yahoo Messenger, or any of the other most popular proprietary instant-messaging tools. Pidgin is a free, user-friendly IM application that can handle just about any messaging protocol you're likely to come across. This makes it especially handy if you trade messages with people on more than one IM system -- which, I'm guessing, is true of most IM users these days.

I could bore you with all of the usual caveats about these products: They won't make everyone happy, and they will probably make some people very unhappy compared to the proprietary software they are accustomed to using. One thing about open-source software, however, is that it doesn't cost you a thing to try it out -- any way you want, for as long as you want.

Naturally, these five applications aren't even the tip of the iceberg. If your current annoying-software pick isn't on this list, maybe it will make the next one; I'll get around to some of the others as time permits.