allow user to sign up for different role I am new to drupal, so any help would be appreciated in advanced. My requirements are as follow.

1 happened in signed in user environment.
1 :" there must be groups. and they will be assigned under one user (role: manager) only he can manage the user (create,update,read and delete)" - need to be solved

* There will be a user with (admin permission) will be able to manage groups including manager * solved**

in home page : guest environment
2: "User must be able to choose which group they wanna go in: But they might need to be approved by group manager or admin before they can use their account"

for 1: i found some modules like organic group/sub-user

for 2 : i found some modules like multiple registration/ advanced registration (i don't think that gonna make it)

So please, Drupal masters, if you happens to know how to full fill those requirement with drupa stuff like Field, views or whatever. Do let me know. THANKS!!
Organic groups can do it however it requires a legthy process form the user. Eg. a manager must create a group (the creator of the group is also the manager of it by default). Then users that wish to join the group must go to the page of the group and request to subscribe. The good thing with og is that it also supports the concept of og content. That is you may create a content type and denote it as og content of a specific group. Then only the members of this group will have permissions to a node of this content type.

Another option is to use a plain old field in the user registration form that will be a list with the desired role. You can do this by going to the user configuration page. Then you can add a rule to automatically grant the requested role to every new user (a simple value comparison in rules) or create a manager view so the manager can see which user wants a role and grant it. The vbo module can help the manager in the later case.