I was told I can send a check from my bank. Is this true? How long does it take for the money to appear in her account after depositing it?
Last time I paid in a check it took eight weeks and the best part of a hundred dollars to clear.
Also if this is not possible what other methods. Wire transfer I suppose. What information is needed?
You will need her IBAN account number and the name and the SWIFT code of her bank. And the name she has the account in.
Personally I'd be tempted to just send the money direct to the US consulate here. Or better yet I'd be trying to find out if there is a US account which the money can be transferred into.
We want to send my wife's mom money to get a visa to visit us
Assuming that she wants a non-resident's visa, it seems that you need to either get the money to her (and then she can pay at the post office) or you can just pay the money direct yourself to:
Ambasada USA 00-540 Warszawa Al. Ujazdowskie 29/31,
Citibank Handlowy w Warszawie SA,
account no: 33 10301508 0000000500350016.
Details are here: poland.usembassy.gov/poland/mrv_fee.html
If she knows anybody who has a paypal account, I'd suggest using that.