If you want to know how your website is preforming in terms of the search engine rankings, then there is software out there that will find this information for you. Depending on how many terms you want to track and how in depth of an analysis you want should influence your choice on which software to go with.
Some great marketing companies have even created their own ranking software that often works better than many off the shelf ones and allows them the control to add in additional features if there is the call for it.
With any ranking software, there is a strong chance of error and this can be caused for many reasons. You should also be aware of the risks involved in using some ranking software. If the software is ran off the same server that your website is hosted on, you may find that your server becomes black listed for running too many search queries and this can in turn black list your site so it is very important to have it set up correctly by a trained professional.