The PlayStation 3 received a big price reduction in September 2009 when the new slimmer console was released. Naturally, you'd assume that two years later we should get a price cut to around $199 or maybe $249 at E3, but it's looking unlikely.
Sony just announced a $170 million loss due to the PlayStation Network hacking fiasco, which is still on-going. On top of this they only just started making money on each console sold, something which Microsoft and Nintendo achieved a long time ago in their product life-cycles. Sony could possibly be able to handle a $50 cut in price, but it won't be announced at E3.
We'd guess that Sony will not announce any price cut at E3, but wait a little longer and announce it at GamesCom if it will happen at all. The main reason behind this is because it is closer to the holiday season. Another piece of evidence that it is more likely at GamesCom is that Sony already did this when they announced the release of the slimmer PlayStation 3 at GamesCom 2009.
Instead of offering a lower price, Sony could offer more value for a PlayStation 3. For example they could offer a high-end bundle with a a 500GB HDD, but this is probably unlikely because they already of more HDD space with their current high-end bundle than the equivalent Xbox 360.
We're expecting NO PS3 price-cut at E3, it's more likely to happen at GamesCom, if at all.