Useful astro-ph links:

Today's papers

Papers submitted during the last week, or during the current month

Search form, by author/title/abstract

Look up an abstract (and thence the entire paper) by entering the paper's "phone number"

The NASA Astrophysics Data System (ADS) maintains a searchable bibliographic database of published journal papers. Each entry generally contains bibliographic information, an abstract, a link to the electronic version of the journal article (when available), a scanned or PDF version of the journal article, as well as a list of entries for references by that paper, as citations of that paper by other papers.

Useful ADS links:

Search the database by author, date, title words, and/or astronomical object; highly configurable search parameters and weighting if desired

Look up an entry by journal name, year, volume, and page number. Excellent for quickly finding online a listed reference in another paper (since this search form is in the same format as that of the References section of a typical paper)