Bucking the trend of the most recent round of polls, the new Fox News/Opinion Dynamics survey (August 19-20, 900 RV, MoE +/- 3.0%) shows Obama ticking up ever so slightly against McCain:

Obama 42 (+1 vs. last poll July 22-23)
McCain 39 (-1)
Undecided 19 (nc)

According to the survey, Obama increased his support among Democrats slightly (to 78% from 75%), McCain lost a touch of ground with Republicans (to 82% from 86%), while the even split among Independents remained basically the same (31% for Obama, 30% for McCain).

The poll also showed Hillary Clinton beating McCain by a similar margin (46 to 43), winning 81% of Democrats but losing Independents to McCain by six points (35 to 41). On a related note, 56% of Democrats say Hillary is Obama's best choice for VP.

Overall, Obama's lead now stands at 1.5% in the RCP National Average.