remoting ---(same platform )
webservices---(any platform)

asp.net web services are accessed using HTTP only.while 
remoting accessed over any protocal like TCP,SMTP,HTTP.

webservices are stateless,where as remoting has support 
both stateless and with state,which is achieved using 
singleton,singlecall.

singlecall:object doesn't maintain any state bitween calls.
bcoz it maintains instance instance for every call.

singleton:it maintains single instance for all client 
request.it is useful when you need to maintain shared data
or resources b/w clients.ex:-windows media player

no need to build webservices in .net it allows other 
platforms webservices also.where as remoting build in same 
platform only.