obviously i won't get a first page ranking just through ppc...but is it safe to assume that the traffic i get through ppc will lead to a higher pr? also, what other sites besides alexa give me accurate page ranking? thanks!
not necessary true. depending whether the ppc has your link as hyperlink to your site and not some kind of redirect form. by the way alexa does not give you accurage page ranking. it is mostly abused by webmasters.
there is not any relation between Google PPC & Google Page Rank. Google PPC is working based on Javascript and robotx exclude the javascripts. So, your web site links on other side through PPC will not increase the page rank. For to increase page rank you need to do directory submissions, article submissions, you can also buy links from high PR sites.
PPC Click does not directly give you higher PR, or get you higher on the natural serps. However, I wouldn't discount it entirely. Lets say you bid on the keyword "link exchange {keyword}". Or "free content {keyword}" You could probably get some links from your traffic that way, which would get you a higher PR
Search engines are more advanced these days. They can easily differentiate good from bad.Try to write good content and make it SEO friendly. You will see good results in the long term.