BtoBonline cites a ComScore study revealing that 63% of Internet users in the U.S. conduct an online search (as of July 2006) -- which is up 43% over the year prior.
While this study focuses on all local searches (ie., not just business-to-business (B2B) searches), it might give you some encouragement to test some local search PPC campaigns, if you aren't doing them already.
If your service has geographical limits to your local area, then of course this makes sense to try.
But even if you offer services nationally, you might think of targeting local search campaigns in key geographical areas for your target market profile (and measure your results).
For example, if you specialize in services for agricultural-related firms, you might try local search campaigns in cities/regions/states that are likely to have companies in your target market -- perhaps the bread-basket areas of Lincoln, NE or Des Moines, IA.