During the Search Engine Q&A on Links session here at SES today, Tim Mayer from Yahoo said his company is launching (not live yet) Yahoo Site Explorer that provides webmasters and other interested parties with linkage data.
From a SES Session Summary:
Yahoo Site Explorer is a place to see which pages Yahoo has indexed. After clicking "Explore URL" you'll find the number of pages found in the Yahoo Index and also the number of inlinks. You can sort pages by "depth," submit URLs, and quickly export the results to CSV format. Site Explorer is also supported via an API.
Postscript From Danny: The new tool will also allow bulk submitting of URLs. Expect further details when it goes live.