LinkAssistant SEO Tool allows you to check your site rankings in Google, Yahoo and MSN for as many keywords as you need. LinkAssistant (LA) has a special tab named "Keywords", where you can "Add", "Edit" or "Remove" your key phrases, and also "Check" your website's ranking in any of these three SEs for these keywods.
PS: LinkAssistant checks first 100 positions only, so if your website is not in top 100 results for some keyword, you'll see "N/A" instead of a real position.
There is a tool called Rank Tracker which can be downloaded via Google. This works only if you use Firefox though. Once it is installed, it will show up on the bottom of your web browser and you can use it to check your rankings on the three most popular Search Engines, Google, Yahoo and Bing.
You can use the Yahoo Position Checker Tool as well to particularly see the ranking of your website on Yahoo. You will just have to enter the URL of your website and it will check the ranking of your site on Yahoo.
How to check site ranking in Yahoo?
