You can search for a niche directory by using the format "keywords + directory" or "keywords + add URL." Please note that some directories prevent the "add URL" part from being crawled.
Also check out business partners, distributors and affiliates. Sometimes they have directories or a partners page.
The Chamber of Commerce is a directory from which it is worth your while to get a link.
Auto Forms and Submission Software
At all costs, stay away from submission software. It has no value and you will end up penalized by the search engines. Also stay away from submission schemes priced at $1 per listing (or similar). Those hurt instead of helping.
If you do use an auto form filler, make sure to vary your information slightly and remove any trails that may indicate software was used. It's generally a good idea to create different descriptions, but if you're extra lazy at least vary them a bit.
On the topic of software, stay away from applications that claim they can help you gain top rankings on search engines. Those go for few hundred bucks, but never get you promised results. Search is a billion-dollar game. A $300 program from Joe the garage guru will not beat it.
On the other hand, there are plenty of useful apps that help with overall SEO tasks. Many can be found for free or at moderate prices.
Quality Game
If you have a quality site, with high PR, but few editorial links, the site may be lacking in trust and get flagged for review. Internally leaked Quality Rater guidelines showed that despite Google's war on spam, it may tolerate some degree of spam as long as there's quality content, aka the formula "quality site + PR only links (non-editorial) = Google tolerance." I won't suggest you follow this formula, since going for PR links can get a site penalized by algorithms first, before human raters, but it's good to know.
Directories are good sources of links, but they are not the core of SEO rankings. You can still make a site rank on directories alone for relatively competitive terms, but it's better to mix these with more editorial links.
Don't make directory buys your primary link building strategy; it's a risky game that can backfire. Focus more on editorial links through content development, and then submit to directories.
Web Directories 
