There's a certain amount of confusion - often exploited by search engine optimisation companies - surrounding the term 'google rank'.
Google rank is a rating given to each individual page that makes up your web site. Your front page, for example, may have a google rank of two, while another page on your site may have a google rank of 5 (the higher the better). Google rank is calculated using a variety of different factors, but one of the main ones is the amount of pages that link to your page, and their quality.
Does having a low/high google rank affect how a page is listed in the google results for a keyword? Well, it plays a part, but it's not a given that if your page has a low google ranking, that it will not perform well for keywords on that page. Equally importantly, it's not a given that your page will perform well automatically if it has a high google rank.
The important thing to remember is that google attempts to provide relevant results for keyword searches - so it takes into account things like your google rank, but also how a keyword appears on your page, or whether a keyword is used in the link text from other pages that link to yours.
So, the lesson? Google rank is important, and is a good indication that your pages are working well on the net (getting linked to etc), but it's not eh be-all and end-all for search engine optimisation.
There are various tools and websites around that you can use to check your google rank for any individual page - always remember that google rank is for individual pages, not for your website as a whole.
The way we recommend is the way that google itself recommends, and that is to download the firefox browser with the google toolbar installed. Firefox is an award winning browser that has a number of advantages over its competitors, and is completely free.
Once downloaded and installed, you can browse to a page using firefox, and in the google toolbar you'll see the current google page rank for that page.