I mainly do .Net development but have just bought an Apple Mac Book Pro and am wanting to do some iPhone Development as well. Is there a particular Source Control Software out there which will handle integration with both Visual Studio and iPhone develeopment (Titanium/XCode) ? Thanks
Subversion will work. Xcode supports it natively, and there are Visual Studio add-ons for it as well.
Subversion has client integration available on both Visual Studio and XCode.
XCode - http://developer.apple.com/tools/subversionxcode.html
AnkhSVN (plugin for VS) - http://ankhsvn.open.collab.net/
You might also want to consider Git - more command line required, but it is also cross platform.
Honestly, I'd take the approach of leaving source control integration out of the IDE. As some of the commentors have mentioned - there are SVN clients that don't integrate but work wonderfully.
TortoiseSVN - http://tortoisesvn.tigris.org/ is just awesome Explorer-level integration for Windows. I know that they are working on a Git client as well.
XCode supports Subversion, CVS, and Perforce. I haven't used Perforce but I can say that the CVS support is awful. The Subversion support is very good but it doesn't have enough features to make it great for anything beyond day-to-day use. So prepare to do more advanced stuff (like merging branches) from the command line.
A bonus is that every Mac has a SVN server built-in, so it makes it an even more attractive option.
Git is nice because it doesn't require a server. And you can push it to a "master" on a remote drive, or a hosted solution like github, etc.
GitX is an excellent frontend on OSX. I am sure there are integrations into XCode but I use mostly Komodo on OSX, so I needed something that was seperate.
GitExtensions has been working pretty decently for me integrating into VS2008.