Ajax: the Microsoft way
For hardcore Microsoft developer, there is no substitute for using Microsoft Ajax extensions. You can start from making your existing application use Ajax through the magic of update panel, get into server controls toolkit supported by vibrant online community and then move your way up all the way to the SOA nirvana. And the best part is that in .NET 3.5 Ajax is not different from ADO or XML – it is part of the core framework. You (and your hosting provider) will get it for free after next upgrade, love it or hate it. You can start investing in your future now.