Your best bet would be to try a variety of places and find out what works best for you. You won't find one magic bullet that works for everyone equally. Trial and error.
The best market to sell VPS packages and shared hosting is to NEW businesses. "New" business leads can be purchased for as low as $0.14/lead from the Business Journals. I'd venture that 30% of those will have phone numbers.
Also, MOST cities have a public records office and you can go in at any time to pick up copies of newly registered businesses. You'd want to talk to the County Clerks office. I believe most chamber of commerce memberships grant you access to a list that's published monthly.
Also, InfoUSA has a HUGE database that you can quickly build lists and get your information daily, weekly or bi-weekly if you wanted.
The best way is to first start marketing your business in your local market through print media and references because it always give you more business than online.
However, if you are already a trusted name in your local area. Then you should be partnering with Google to market online, it will list your site in trusted area so will give you more business.
google adwords is probably the fast and most efficient method to sell your services. once you get customers you can keep working on other methods to promote your website.