According to a pair of news stories on CVG, Valve Software and The Creative Assembly are eyeballing cross-platform play between Xbox 360 and PC. The Creative Assembly, developer of the Total War RTS series, is certainly thinking of cross-platform game play for its RTS series, according to Brendan Rogers, designer and artist of Medieval II: Total War expansion Kingdoms. "As a games developer with an established series of games like Total War, then obviously the cross-platform potential appeals." While TCA is favoring it, implementation won’t happen for a while; Rogers simply stated, "bringing the Total War series to the console is not something that is on our radar right now", but does state that he doesn’t "see any major incompatibility issues with strategy games on the console".
As for Valve, it’s a little further down the line in terms of implementing cross-platform gameplay — it’s technically done for Team Fortress 2. Robin Walker of Valve reassured that controls won’t be an issue since the folks who ported the Half-Life games to Xbox have been working on Team Fortress 2 for the 360. "And so the same guys that did that [Half-Life for the Xbox] are working on TF2, we have all the tweaks we did to the controls, the sticks and everything. One of the advantages of TF2, relative to something like Counter-Strike, is that it’s not so much about aim." While it’s technically done, plans for full implementation may or may not be in the final release of Team Fortress 2 at the end of this year. That’ll certainly be something we keep an eye on.