I think you want to check SERP. Then you need now the keyword of your site. Try some online tools for that.
Yahoo had tested an alpha version of algo but never really went through with PR styles - now it's BING ran
If you are using mozilla firefox browser, you can use search status addon, It will display PR and Alexa ranking.
lol, pagerank is not a Yahoo thing...It's completely Google. Pages can only have a Google pagerank, not Yahoo.
Yahoo does not have any page rank system till now. Google only providing page rank for every webpages.
Yahoo does not has a "PageRank" but has its own similar one called "WebRank". You can check by use this tool provides from Digitalpoint - Yahoo! Web Rank Checking Tool
i agree with above posts .yahoo do not have any page ranking system like google but i do not know about bing and other search engines.
If it's backlinks you're interested in, then there are lots of backlink checkers that will give you a list of links from all the major search engines (the SearchStatus toolbar has those + PR, Alexa, Compete, and MozRank). If it's SERP, then you could just search for your keywords and see where you appear. PageRank is just a Google thing, though. Yahoo doesn't offer any information about how important it thinks your site is.