there are so many numorous changes in API
1.due to these changes CLR got the full control of memory 
management,thread management, and in security.
2. Introduction of generics
3. Click once deployement
4. CLR integration
5. Db caching techniques
6. Support to new controls like sql connection, log viewer, 
str

In terms of .NET Framework1.Introduction of Partial 
Classes. (Partial Classes allow you to implement the 
functionality of a class partially allow other developers 
to implement the other part.).2. Generics.In terms of 
ASP.NET Framework:1. Ability to post the data from 
from .aspx page to another page directly using the 
attribute.2. The output in XHTML and improved support for 
Browsers.3. Introduction of new controls like GridView, 
FormView,DetailsView4. Ability to write asp.net pages in 
various .NET languages. (.NET 1.1 forced the developer to 
use a single language thro' out the project).
 ip controls

One is dynamic menu. We can create dynamic menus using .Net 
2.0 but not with 1.1

Nullable types are new in .net 2.0

Asp.net login controls are introduced which are more secured
for authentication.

In .Net 2.0 there are numerous changes over .Net 1.1. These
are:-->

1)  Nullabale type check.
2) Generic Class.
3) Partial Class.
4) Runtime debug and modify.
5) debug sql script.
6) login Controls.
7) Navigation Controls.
8) Define classes in app_data folder that makes the classes
define in it to be as a Compiled dll.
9)Themes.
10) Browser settings.
11) Master Pages.
12) Global/Local resources.