I live in Alabama and have rented a home for 29 months. Sunday we were informed by our mortgage broker that the owners wanted to come in on Monday and see the property the just inherited from there father. Then on Tuesday a realtor called and told us that he would be by Friday to get pictures and to put up for sale signs. Do we not get any kind of notice or can they just come in and do this in one day. Our lease has expired and we are on a month to month basis.

Do you have a lease or are you a month to month renter? They should give reasonable notice of their visits and inspections but as to selling that is their choice. However, if you have a valid lease the buyer gets you as a tenant until the lease runs out. Who knows, the next buyer could be an investor also looking for rental property too

Our lease was up in march and we are now month to month. Do they by law have to give us any notice that the realtors are coming over to put out a for sale sign? (Which means we have to be available to show or be willing to let them in to show the house.)

They must give you 30 days notioce to vacate. If you fail to vacate after 30 days then they can evict which could take another month. You are not required or needed much less wanted to show the property. That is the job of the real estate broker. That broker will have a key and can show the home with you present or gone but they are supposed to give reasonable notice of the showing. The term reasonable is quite vague and that term was picked because of that.

Our lease has expired and we are on a month to month basis.

That partially answers your questions. As a month to month renter your tenancy can be terminated on 30 days notice.

As to owners, realtors and buyers coming by, they can't just drop in. they have to give you reasonable notice which is generally considered 24 hours.

... That broker will have a key and can show the home with you present or gone...

I don't agree that the broker can show the house whenever he wants. For a rental property, the realtor stands in the shoes of he owner. The LL can't just walk in, unless it's an emergency. I would insist upon at least 24 hours notice.

For example if they call on Tuesday that they will be there on Friday, that is a large notice and they can come on Friday and take photos.

They can show the home if you are not there, and often even ask you to leave if possible to show the house, ( you are not required to )

This may be a good time to consider buying the home if you have the ability

AK did you miss the second half of that sentence? "but they are supposed to give reasonable notice of the showing" I want the OP to know they do not have to be there during the showing and the realtor can show in their absence.