You have a good leads pipeline and people are contacting you to buy your services.
A rule of sales is that larger the sale price longer the period the client will do a due diligence. So you need to keep a system to keep in touch with your client during this sale period.
The biggest name in hosted CRM is Salesforce. I dont recommend them as they are built with a larger sales team in mond, and if you have only a single person doing sales, it adds too much of a overhead.
I have used a simple CRM like [Highrise](http://www.highrisehq.com/). They make it easy to find your communication with a client in a single place. I however found even this too much of an overhead. But for most people this would be a good fit.
How I work with our leads using my inbox as a simplified CRM. Our contact us page has a unique contact address. As we have a catchall email address, this email comes to me, but gets tagged as leads. Our contacts us form also sends to this address, so the tagging happens either way.
I check my leads folder once a day to see if there are any new leads I should respond to. Once a deal closes or falls through, I put them out of leads and into the closed or fell-through folder.