Hi,
I think it would be a pretty good move, but for better understanding I have divided my answer in 2 parts. Hope it helps you!!!!
1) What do Admis do, etc:
As they have already said, it can be as simple as answering the phone and greeting people (really an Admin/ Receptionist job - or like they call them now Director of First Impressions - no joke), or.. add clerical duties - typing, filing... all the way to..... plan international events, presentations, travel arrangements.......
A degree, even not in Business, will certainly not hurt you., but you will have to start at an entry level admin position also.
If you have not done so yet, take some online courses, (free at most local libraries) specially on MS Office Word, Outlook (a calendar-contact program widely use). Excell, Powerpoint, etc are normally used by senior Admin (generally..)
For salary info, good job descriptions, type of salary to expect in your industry/region, etc... I have found a pretty accurate site: www.payscale.com. Take a look, it is a good job research site. You can even check if the salary they are offering you is in range for your location/experience/industry.
NOTE:
Only do the FREE profile. They try to redirect you to their PREMIUM Salary Report. DON'T pay anything, you can still get ALL the information you need from all the FREE reports you are allowed to access.
2) Good Job to start: YEP!!
If you are finding it hard to find an entry level job in your field, it is not a bad idea at all ( if you don't mind starting at an entry level admin), but you would get MUCH more out of it if you try to get a position in a company in YOUR FIELD of study.
Let's say, if your degree is in chemistry/biochemistry, try for a position with a Pharmaceutical company.
If it is in earth science, try applying for a gov/state/city job at their Environmental, Geo/etc offices. etc. etc....
You can Google your state/city government employment links, and then just apply for an Admin Assistant or even a general office work with them.
Why this could be a win/win situation.
By working as an admin in a company in your industry sector :
(A) When you go into Graduate School, you will have some years of interacting, in the real vis academic world, with the type of people/personalities/office environment of your field of study.
(B) You will have (even if only from the sidelines) a peek at how other professionals in your field work/interact in actual companies in your chosen field.
(C) You can start networking!!!!
Show you are a dependable employee, then start talking to the professionals and tell them what your plans are for grad school and ask them for advice.
Do not ask them for a future job!!!! They will clam up!!
Just make sure you tell them that you have seen them work and would very much respect their advice (perhaps you can get a mentor - do not tell them his though :)
Network as much as possible, as time passes make sure the people you respect know about your degree and future studies. you never know how someone already in the field may help you or even give you a good reference in the future.
So work hard at building a good solid reputation, remember to offer these professionals assistance with their projects (even if it is filing, show interest in their work, if you have any free /downtime, they normally will remember you.
(D) All this experience may even help you confirm or decide to make some changes concerning your chosen graduate field.
GOOD LUCK !!!