There is no limit to the number of records, rather that an Access mdb can be up to 2Gb. That can actually be gotten around through linking to multiple mdb's.
To be used by multiple users, you would split the application into a back end containing the data and a front end containing everything else. Each user should have a copy of the front end on their PC, linked to the back end on the server. Do NOT let multiple users open the same copy of the mdb on the server. It will become corrupted.
The theoretical limits on data storage in Access are constrained by the data storage. As pbaldy suggest if you use the default data storage method in Access (JET) limits you to about 2GB of data, but Access can easily 'talk' to other databases, such as SQL server, DB2, MySQL etc... whose limits are controlled by that software application.
If you are seriously concerned about storing that amount of data then you should consider using a server database, and steer clear of using queries stored within Access. Its fine to proove queries using the query designer but you will have severe performance problems accessing that amoun of information.