Chris Anders - Internet Strategy Consultant

Google specifically state that you shouldn't use automated tools such as WebPosition Analyser to assess where you are in search engine rankings.  Whilst I'm unaware of any sites that have been penalised as a result of using it it's possible that you could be unlucky.  If you are only tracking a few keywords however the easiest way to check your position for a given keyword is to take advantage of the Google "Advanced Search".  To do so simply click on "Advanced Search" next to the Google search field and then change the "Results per Page" setting to 100, enter the search term and hit "Advanced Search".

You can then use your browser's Edit / Find on this Page function to enter your web address and jump to the first occurence of your site within the results.  If your site appears mid way down the page rather than count down change the "Results per page" setting to e.g. 20 or 50 and then jump to the approximate position and count down to where your site appears.

If your site doesn't appear in the top 500 results it probably doesn't make sense to go any further!  Bear in mind that the bulk of visitors click through to results shown on the first page and so if you are on page 3 or 4 it's unlikely you will get any traffic from a paritucular keyword unless people modify the search term and it becomes more relevant to your web content.