ISPs can get very twitchy about you sending out large amounts of email, so be careful. Also be careful that those on your mailing list really wanted to be there and know why they are there. Otherwise they will often flag your emails as spam.
IMHO, it's better to use a recognized provider for mailouts like this, such as MailChimp or CampaignMonitor. It's very cheap, and there are lots of benefits, including not getting in trouble for sending large amounts of email, tracking opens etc.