We are aming to develop a computer-based consultant system which helps novice computer users to achieve their task goals on computers through natural language dialogues. Our target is spoken Japanese. To develop effective methods for processing spoken Japanese, it is essential to analyze real dialogues and to find the characteristics of spoken Japanese. In this paper, we discuss the design problems associated with constructing a spoken dialogue database from the viewpoint of advisory dialogue collection, describe XMH (X-window-based electronic mail handling program) usage experiments made to collect advisory dialogues between novice XMH users and an expert consultant, and show the dialogue database we constructed from these dialogues. The main features of our database are as follows: (1) Our target dialogues were advisory ones. (2) The advisory dialogues were all related to the use of XMH that has a visual interface operated by a keyboard and a mouse. (3) The primary objective of the users was not to engage in dialogues but to achieve specific task goals using XMH. (4) Not only what the users said but also XMH operations performed by the users are included as dialogue elements. This kind of dialogue database is a very effective source for developing new methods for processing spoken language in multimodal consultant systems, and we have therefore made it available to the public. Based on our analysis of the database, we have already developed several effective methods such as a method for recognizing user's communicative intention from a transcript of spoken Japanese, and a method for controlling dialogues between a novice XMH user and the computer-based consultant system which we are developing. Also, we have proposed several response generation rules as the response strategy for the consultant system. We have developed an experimental consultant system by implementing the above methods and strategy.