FWIW - I spent a couple of years as a Data Specialist working with companies who have mobile workforces and setting them up with wireless (cellular) solutions, be it VPN access, GPS routing, etc.
Your phone, unless it's a PocketPC phone, does not have the memory to d/l email. Also, the passport/.net system that ms uses appears to be incompatible with most phone/wap browsers, which means you can't use CDPD or GPRS (your cell phone's data transmission method) to read hotmail.
Yahoo should be better, but check your ISP. I have cable internet and get seven email addresses free...