Can I have both IDEs for different framework versions in the same develop machine and the VS 2005 will work ok?

Yes, you can have both VS 2005 and VWD Orcas Express on the same machine ("side-by-side installation"). However, if the only reason you want it is to target different framework versions, then you no longer need to do this. VS 2008 ("Orcas") can target both 2.0 and 3.5 versions of the framework. It's called "multi-targeting". When you are creating a web site, you will be able to choose which framework version you want to target. Please see ScottGu's blog for more info:

http://weblogs.asp.net/scottgu/archive/2007/06/20/vs-2008-multi-targeting-support.aspx

If you decide to go with side-by-side configuration anyway, then read this. With the current (Beta 1) release of VWD Orcas Express, there are some minor issue with side-by-side installation with VS 2005. However, Beta 2 of Orcas will come out shortly, which fixes most of these issues. I am not going to promise there won't be any issues at all, but this is definitely a supported configuration.

in fact, I would like to play a bit with LINQ without lost my VS 2005 instalation

leonibr:

in fact, I would like to play a bit with LINQ without lost my VS 2005 instalation

Thank You

You can definitely have both on the same machine. As I mentioned though, I would wait a few weeks for Beta 2 to come out. So far it's looking really good, although I can't give you any guaranteed release dates. Beta 2 of Orcas will co-exist much nicer on the same machine as VS 2005.

 Thanks,
Alex