The first two (of five) reminders that Mega Man 9 is not a retro title -- also known as premium downloadable content -- is available now on WiiWare and will be coming to Xbox Live and PlayStation Network on Tuesday and Thursday, respectively (via press release). As previously noted, you can expect Endless Attack (300 Nintendo points) and Proto Man (200 NPs) this week. Proto Man has a charge shot, slide and a reflective shield, but he also takes double damage and is knocked back twice as far.
The remaining DLC -- Hero, Super and Special modes -- are expected October 20 for WiiWare, with the XBLA/PSN content presumably coming the same week.
Gallery: Mega Man 9 DLC