There is a need for bookkeeping service a lot of people want to do their own books and when they realize that they have no clue what to put where then they call a bookkeeper or accountant. If you are going to do this as a service then you should consider adding other services like daily money management. Typing would be another good one to add and tax consultations and preparation. You can make this work with a little creativity and think outside the box for ways to make your service a niche. Good luck.
I can tell you definitely there is a need for bookkeepers. I do this as a part-time business myself. I have accounts that are older that 10 years. I found that one usually leads to the next (word or mouth). I've turned down manys just because of no time, after all I do have a full time job also. I'm an accounting database analyst. They find out I can write an accounting database and then I'm hired to write membership and payment databases etc.
Watch your local papers, find the ads for part-time bookkeepers. Non-profits always need part-time honest people for this. They have board of directors that can network you into other businesses once you have proven yourself worthy of trust.
I work currently 3 part-time bookkeeping jobs and 1 waiting for me. I do most of the work at home. My full time job is also a work at home position for the state (not the one I live in). I don't need the extra jobs but it gives me the extra to have a nice car and max out my 401 at my full time job.
So as you can see, bookkeeping is alive and well. I think even when I retire (someday) I'll still have a part-time bookkeeping job.