In the 3.5 Player's Handbook, the entry for the feat Improved Overrun on Table 5-1: Feats (p 90-91) states the benefit as:
+4 bonus on overrun attempts; no attack of opportunity
The full description for the feat (p 96) describes the benefit as:
Benefit: When you attempt to overrun an opponent, the target may not choose to avoid you. You also gain a +4 bonus on your Strength check to knock down your opponent.
The SRD posted on d20srd.org agrees with the full entry for the feat. Is the table just incorrect or do all benefits apply? I have looked in a couple of errata, and while there are adjustments to the overrun action, there is no change to the Improved Overrun feat.