Can my email provider know that I am using gmail; if so, can he read it?
Bruce

Without additional details, it would be impossible to answer this question.

Hypothetical, you are on a college campus with college email.  You
connect to email via the campus network.  The school could monitor all
of you internet traffic and if you went through a proxy server before
hitting the internet they could monitor everything....

How do you connect to your email provider?
Are they tied to you internet connection?

If by "email provider" you meant you ISP, then yes, your ISP can tell
that you are using Gmail as they have the capability to see all of the
web sites that you visit (not just Gmail).  As far as reading it goes,
that is a little more complicated.  Gmail uses a secure connection, so
it should not be possible for anyone to read the actual content of
your messages; that being said, nothing is impossible with computers
and the internet, and there is no such thing as anything that is
totally "secure" online.  As the old saying goes, don't write anything
that you wouldn't want your mother to read.

To answer your first question- yes. Your school or ISP can see that
you have gone to http://gmail.com or whatever address you enter.
However, once there, the data is then encrypted using an SSL
certificate. By examining the certificate (making sure that it is from
Google, not expired, etc.) you can ensure that the data transmitted is
not seen by any third party. Ensure that no security warning come up
when visiting the site as that may mean a "man in the middle" attack
is occuring. This is when a certificate is spoofed and someone is
watching everything (including your mail).

Within 1 year all universities and ISP's in the USA will have to have
provided the hardware for all outgoing communications to be read by
the security services almost remotely. i.e. ALL outgoing packet comms
will be amalgamated through a single router for remote evaluation.
 (i.e they can read yr mails and hear your internet phone calls).

1) http://www.nytimes.com/aponline/national/AP-Internet-Calls-Wiretaps.html
2) http://www.nytimes.com/2005/10/23/technology/23college.html

Apologies, but you may have to register to read the articles - I am
already registered.

What about using some sort of web proxy service?

Theres a lot of them out there which let you go to websites anonymously..

Try 
http://www.letsproxy.com
http://www.intelliproxy.com

By the way almost all proxies are logged (not sure by there were
information that they could belong to security services to trace
people who do something illegal)and theres no problem to find a person
afterwards.its better to use proxy chain using special software(or
like hackers do to install a trojan with proxy to some other person's
pc and work with his address:).