It is still not yet officially confirmed by USCIS, but there is a news item here that infers, cap on H1-B visas could be reached on Day 1 itself. If that is true, then USCIS would take all applications received on 2nd and 3rd of April and use lottery system to pick eligible applications.
USCIS began accepting petitions for fiscal 2008 H-1B visas on Monday. It will accept more petitions than the allocated spots because not all the petitions will be approved for the actual visas.
However, if the mailman's bag is any indication, USCIS may have already reached it's total of petitions, says a USCIS spokeswoman.
USCIS service offices in Vermont and California -- where petitions for H-1B visas are collected -- have reported "significant increases in the amount of mail" they receive, she says. "We've hired extra staff to work in the mailroom and sort through it," she says.
It may take a day or so, but it's possible USCIS has already received the maximum number of visa petitions. "Right now, H-1B is still open," she says. "But once we state the final accept date, we'll stop accepting them and petitions will be rejected," she says.