How to convert a string to sObjectType

Here is the way:

// I have Account name in String
String objectStr = 'Account';

// Convert to schema.sObjectType
Schema.SObjectType convertType = Schema.getGlobalDescribe().get(objectStr);

// Create an instance of that type
Sobject genericObject = convertType.newSObject();

// or if I know it is Account !! why making Sobject ?
Account acc = (Account)convertType.newSObject();

An alternate way to do this without going through Schema.getGlobalDescribe():

String myString = 'Account';
SObjectType sObjType = ((SObject) Type.forName(myString).newInstance())
                                  .getSObjectType();

speed comparison between above and getXXDescribe methods